3rd party ef glass for R8?

Heys guys, i have recently bought a canon r8 alongside the rf 35 1.8. I am looking to get a decent zoom lens soon but the problem is that the rf zooms canon makes are very slow and the ones which are fast are way out of my budget. This got me thinking about ef glass and also 3rd party ef glass to use with an adaptor for my R8. Would this be a sensible decision? And if so what lenses would you guys recommend. For context i can stretch my budget to $500 at max.