it'd be a season long effort probably to teach you everything they want you to know/be able to do.
so you'd probably benefit from getting experience on basically any team you can get that's not gonna die, which means lowering your expectations from mid-high to low-mid teams.
Also I can understand why it's hard to find a team to get the experience you need to find a team, which is why suggestions like making your own team or joining newbie mix teams are really good.
For example with myself and a few friends, we pretty much knew we were nobodies, so we tested the waters with our own sixes team, called it egg salad dressing, worked our asses off and eventually made our existence known, which led to tryouts for some of our members for s23, now that the team has sadly parted.
Hoping to get the easy route of landing a spot on an established team right off the bat with no history is honestly something that could only come through a ton of raw talent, a ton of luck, or a ton of circle jerking.
Something I've learned about playing in the tf2 community though is that networking as a social skill actually is important, even if you don't view it that way. Make friends, join pugs and try and make sure people get a good feeling for how good you are as a player and as a person.
good luck.