Ps5 and wifi speeds in general

Last year upgraded to bell fibe 1.5 gig. My ps5 is upstairs so yes I know wifi can drop and wired is not an option. I can get about 200ish down and about 70ish upload on my ps5 but online games lag worse than when I was running 30 down. Anyone know how to fix this? I also just ran recent speed tests and I'm only get about 450 down and 550 upload even standing next to my wifi on my phone should I not be getting better speeds in general? Paying for 1.5 and only get 1/3 of it seems wild, I used to get at least 900, do I need to call them? they just keep telling me "there's too many devices connected" whenever I do ask