High input/output (causes studdering)

@EA_Atic I'm not too tech-savy, so maybe I shouldn't draw the conclusion that it's the I/O/server connection, as it could be something else. I actually had the game framelocked and not set to performance mode in control centre, so now I'm at about 290 fps at the highest, and 130 when loading into the map. Actually complete overkill when I've only a 144hz screen.  My internet is actually way better than I expected (though I doubt it could hit these scores all the time), and when I went into firing range just now I only had about 40 ms of ping.

The lag, again, is extreme: My character bobs back and forth and when I shoot there are pauses of about half a second between the bullets being expelled and the damage numbers appearing. It's like this most of the time I try to jump, but a few days ago I gave it another try and I had no issues. Today, it's unplayable again. I'm using a VPN, but that shouldn't be a problem, as I always make sure to connect to my nearest server geographically. I've also tried turning it off, but that made no difference. I also full re-installed the game, but to no avail.

I feel like it started happening a few days into the latest major patch, i.e. the genesis patch. I definitely played the old maps a couple of times without issue.

This seems like it HAS to be some other, less obvious issue.