The one plugin to use, which is entirely free(!), is Litespeed caching for WordPress. It works regardless of you running OLS too, bar the direct tie-in to the caching service.

With that and Cloudflare caching, I get to nearly 100% on pagespeed.web.dev, even for crappy sites with terrible themes.

With OLS as a stack, I can probably get a lot more websites onto the same server without impacting on performance. Probably around 40% more according to some research I did.

Interestingly, plain WordPress, with its stock themes and without Redis and Cloudflare get's nearly 100% on pagespeed.web.dev. At least in my testing, it suggests that the quality of the theme and plugins in use play a critical role. If only customers paid attention to that and spent money wisely with decent web devs instead of buying dodgy themes and plugins ;D

What's your experience? Why do you want OLS?