I've conveniently had this issue almost only on official days and at the most inappropriate of times too.
What both me and my teammates who've also had this multiple times before started noticing is that none of the fixes actually (seem to) fix anything. Instead the issue solves itself after a bit of time has passed, even if you don't try any of the fixes.
The thing is that trying all these fixes, restarting your computer and launching tf2 etc. tends to take quite a while unless you have a pretty decent SSD.
So by the time you've tried all these things the issue has ended up solving itself regardless.
Usually it seems to take anywhere between 10 minutes and 1 hour but rarely anything outside of that time frame.
I don't know if any of the listed fixes for this issue might actually just speed up the problem being resolved, rather than solving it instantly. However I've never noticed a difference in time it takes for it to resolve regardless of what I've done about it.
The only workaround for this is playing on an alt from the looks of it.
Although sometimes your alt will quickly get the issue as well if you just out and switch from your main right away.
I'd say that logging out from your main, restarting your computer and then logging in to your alt would be a good idea.
You could probably try throwing in that cmd fix as well before the restart if you can bother.
These are mostly just my own speculations though, if I'm completely miss-informed here I'm sorry.
The only thing I can back my statements up with is that I've simply had these issues a lot and during those times tried quite a lot of things without any apparent difference in overall results.