I had this same problem a few months ago, after i bought a new bigger monitor.
I was playing GW2 on a RTX 3080 on a 27" 1440p monitor, i played GW2 on 1440p with no problems.
Then i bought a 32" 2160p monitor, i played GW2 on 2160p. That went well for a few days but then i started to get the same problems as you described.
I searched hard to find a solution, but i did not succeed (yet). So now i play GW2 on 1440p on a 32" monitor. Not perfect, but still great... and stable.
So my advice to you is to play GW2 on a bit lower resolution, just to see if it fixes your problem.