Considering just how old the game is combined with the fact that it's not nearly the cash-cow some people make it out to be these days, being "Free To Play" now; I don't think Valve has much incentive to actually fix it beyond this point. Thanks to the source code leaking in 2020, I don't think they really can. The TF2 community can mitigate the problem a little by using custom community servers to combat the bots, but I think they're shit out of luck if they think Valve plans to wage a never-ending arms race against the bot programmers. It's sad, but TF2's been around for almost 20 years. Its time has well and truly passed, and I'd say it had a pretty damn good run for a game of its ilk that none of the thousand of imitators every publisher keeps farting out these days will ever live up to.
TF2 was a watershed moment that captured lightning in a bottle and made a huge cultural impact on gaming, independent animation and internet culture. It was one-of-a-kind, but it was never going to last forever.
Don't cry because it's over, smile because it happened.