Stuck in AdSense hell (terrible RPM + tanking site speed). Advice?

Hey guys. I run a tech/hobby site with around 40k monthly sessions (mostly US/UK traffic).

Right now, I’m stuck on standard AdSense and the revenue is awful ($3.50 RPM). To make more, I tried adding more ad units manually, but it completely killed my site speed - mobile PageSpeed dropped from 80 to 44, and Core Web Vitals are flashing red.

I don't qualify for Mediavine yet. How do I increase revenue without destroying my SEO and traffic?