pancake_stacksThanks for updating the commented file.
You should also maybe look into going over your interp section. Having 0 interp being tagged as "recommend as LAN only" isn't the best advice. I personally can't snipe consistently with a lerp higher than 10 (your cfg without any tweaks defaults me to 21 lerp on a pub server, too high IMO), as the hit reg legit feels broken when using a high lerp and you're facing other snipers that are constantly strafe spamming, crouch spamming, drop scope trick, etc. I personally like the lowest possible lerp possible on all classes, as it lines up the hitbox with the visual model as close as possible.
It's obviously placebo in your case, if you say there's a difference past 10ms. The lowest TF2 can go is 15.2ms. There is a reason why interp exists, and why I have that recommendation. Extrapolation is much more harmful than interpolation, especially since you have server frame rate drops and variance regularly on most servers.
The latest version of the config has 17.9ms interp, not 21.
The server is aware of and accounts for client side interpolation latency, so the hitbox argument is invalid entirely for hitscan. And for projectiles, the difference of like 2ms latency does not adversely affect hits, as accurate trajectory is of utmost importance, rather than accurate position within 2ms, since projectiles have a travel time.