ah, the mouse sensitivity polemic, it never ends
you will most likely recieve the same answer as a lot of people - it's up to personal preference and all comes with practice

I use constant in-game sensitivity and switch it to lower for hitscan and higher for projectiles with button on my mouse. someone else is using low sens for all the things and has a 2 meter mousepad and a separate table for hand and mouse.

120/144hz makes hitscan easier because your eyes track the target more often so it's just easier to actually know where to point.
8inches/360 is a pretty good middle ground, honestly it's just grinding it out and focusing on aiming and not your config.
Make sure to use your wrist when you aim it makes stuff much smoother when it comes to small movements.
Remember that there are players who play with half of your inches/360 and they have no issues aiming, it's just something you aquire over time.

Not too long ago I used to use 4 different sensitivities depending on the class I played, and had no issues switching between the classes, now I use about 6inches/360 on all classes and my perfomance has not worsened.

If you feel like your sensitivity is making you choose between rocket jumping and aiming, go with the one that makes aiming feel better, and learn to rocket jump with it. The limiting factor here would be if your desk space literally isn't large enough to accommodate rocket jumping on a low sensitivity, in which case you're just going to have to suck it up and play with a higher sens. It's definitely possible to rocket jump on a low sensitivity, I have about 20 inches/360 and I can do jump maps and various in game jumps no problem, it's literally just a matter of adjusting to it.

As far as sniping goes, you don't have to choose between flicking and landing precise shots, watching CS is enough evidence of that. Go with a sensitivity ratio that doesn't hamper your ability to look around to a reasonable degree while scoped in, and play with it enough where you feel comfortable hitting precise shots and flick shots.

When it comes to mousepads, they haven't been necessary for a while now, with the improvements made in mouse sensor technology. The most important thing for me when it comes to a mousepad is the texture, since I really prefer a low friction pad to let me make large movements without tiring out my arm as much. If you feel comfortable without a mousepad, and you don't notice any weird sensor issues while mousing on your desk surface, don't bother spending money on one.

144hz makes a HUGE difference. mousepads are pretty important too. some people will use different sensitivities for different classes (usually a high sensitivity for soldier and demoman, and a lower for scout and sniper.)
but it kind of does come down to practice. also crosshair placement isn't really stressed in tf2 as much as in games like CSGO, but if you're really having trouble, try preaiming where enemies are going to be, so you just have to make small adjustments. some people will even watch really good players and try to mimic their aim to get better (b4nny, joshuawn, damneasy, etc.) which might help if you haven't tried that already. but if you're really dedicated to get better, you will get better. keep playing and having fun my dude.

I've used 17-19 inches with soldier being my most played class for about a year with no problems; like #4 said, just learn to jump with the lower sens if that's what works for you. If you can't turn fast enough, keep working those arm muscles.

I'd also like to point out that you'd be hard pressed to find a single good fps player without a decent mousepad.

rocket jumping with a low sens is easier with a lowered table height

^ finding the perfect chair/table height is the secret to all things

Two options:
1. Training. You can either play with low sens and with enough practice you will be able to do 180s again or you just practice with a sensitivity that you can just about easily do a 180 with and try to get consistent aim with it.
2. Mixed movement. E.g. using wrist for aiming, using the forearm to do wide turns.

Hilariously enough, I have the exact same sensitivity as you. 8in/360 seems like a good compromise between hitscan tracking and flicks (both rocket jumps and sniper flicks imo) but I do wish sometimes that I could go lower because my hitscan is pretty subpar. Generally, I feel pretty comfortable with rocket jumping and sniping though, so perhaps you could try some other solutions like a new monitor, mousepad, or even a different posture when playing. I personally found that a larger mousepad has been a huge contributor to consistency. Like everyone else has said, its just a matter of preference and I'm sure you'll find a style that suits you.

I used to have this problem too. I think the best way to do it is find a nice aiming sensitivity and stick to it. The rocket jumps will get better as you play with that sensitivity more and more. If you're constantly changing your sensitivity to try and even it out you will just reset the learning you did with your old sens and you'll be back at square one.

There are both people that are very good at rocket jumping with way lower sensitivities than 8.2in/360 and players that have very good aim with a sens over 8.2/360, so it's definitely not impossible to find a sens that is good for both jumping and aiming.

The only real answer to your question is just find a sens that is still low enough for you to have consistent aim and then practice doing rocket jumps with it.
You really don't need a super high sens to do rocket jumps, 8.2in/360 is easily more than enough, you just need a big enough mouse pad and learn to do big swipes with your arm.
The most you need for rocket jumping is a 180 degree turn and you can do those almost instantly, even with a low sens, if you can move your arm/hand quickly.
And that's just practice.
And it's really not hard to learn either with say a sens of 2 with 800DPI.
Give it a couple of hours with that sens and rocket jumping will become effortless again.
I think your only problem is that you convinced yourself that you can't do rocket jumps with a lower sens, so you give up to fast and increase your sens again instead of just learning to do it with the lower sens.

And about sniping as a soldier main: using a zoom_sensitivity_ratio >1 is definitely a good idea.
zoom_sensitivity_ratio 0.79347(...) is actually a 1to1 translation from your un-zoomed sens to your zoomed sens (due to the changed FOV when zoomed it changes, so zoom_sensitivity_ratio 1 is actually NOT the same sens as un-scoped).
So that's a good starting point if you want a consistent sensitivity across the bord to not hurt your muscle memory, but it's not a huge problem go lower than that if it's only for sniping, just don't go insanely low (like I wouldn't go below 0.5).
Having a consistent sensitivity across all classes is very good, but when it comes to sniping it's just not practical to use a zoom_sensitivity_ratio of 1.0 if you main soldier imo, plus when it's only changed when you're zoomed in and your FOV is changed anyways it doesn't hurt your muscle memory too much.
Just don't go and use a different sens for every single class, that can really fuck up your aim.

thanks for all the advice; (600 pages of blather)