(My last networking class was in college 2 years ago so this might be shaky) Routing is really just algorithms that are run incredibly quickly when you send packets to a remote location. Generally (once again it's been a while) what is prioritized when deciding where to send a packet is the reliability of the connections between point A (you) and point B (nerd server). That does NOT mean it says "well this one is less latency so go there." That's because 99% of internet consumption does not give a shit if something is 140 milliseconds later than instantaneous, but would notice if suddenly a series of packets were dropped in a row (and honestly so would you. I think you'd rather have 100 ping than 20% packet loss.)

You don't even really care about WHERE your packets are going. The issue is the number of stops your packet needs to make along the way. Most of the connections you're taking are fiber lines so your packet is literally traveling at the speed of light, but then it gets to a router and slow poopy computer take 2ms to process and send the signal. Do this enough and you get high ping.

Your ISP won't help you, mostly because they really don't give a shit about your tf2 server ping, but also because the calculation of where to send packets is only run once and given a lease where it won't check again until a certain time has passed (in my experience a week but idk). In theory you might be able to change the MAC address of your router/modem and force the first hop router to run a new calculation of routes but it will likely lead to the same outcome.

What can you do? Uhhh hope US legislature catches up to the needs of the people not the needs of the ISPs. But we got rid of net neutrality so that seems unlikely. As for a solution today you could TRY using a VPN to get alternate route, one that takes less hops, that's what all those "gaming" vpns claim to do. But YMMV and most gaming VPNs are pretty much money grabs.