[2020] Game performance declines with every patch/update

I'd recommend submitting a ticket to CS. Normally they focus on resolving technical issues but they can also provide recommendations on how you can boost the performance of your machine.

The key here is the spec of your PC. You've mentioned that it's "an ASUS laptop that's a few years old" but many laptops were not designed for gaming in the first place. While they may have decent CPU and RAM, very often they have internal GPU onboard that is designed normally for HD video playback and some light gaming.

So, submit a ticket, attach WGCheck report and ask them to help. That's the best advice I can give right now.