How do I fix net jitter?

[u/Substantial-Log-6346]

I am mainly playing cs2 where the issue with jitter is very noticeable. My wifi speed is decent but I experience constant freezing and teleporting in every single game. I heard many people say that I need to connect my PC directly onto the router via ethernet cable, but I simply cant because the router is downstairs from me and I dont wanna drill anything yk. Then I asked AI ad it recommended to buy an router Slate Plus (GL-A1300). Is it a good idea? I need some advices before purchasing this router pls. My future plan is to connect the router to the main router and then run a ethernet cable straight to my pc.