Large websites on WP

Guys, what combination of server + caching plugins + optimization do you recommend for large (500k posts or more) WP sites?

Now I have again taken a seemingly powerful server on Ubuntu 22.04 + nginx + PHP-FPM. Caching Redis plugin + WP Super Cache. And I constantly have problems adding posts via REST API (2-3 posts per minute).
I also used OpenLiteSpeed server with the same negative results.

Are there any verified manuals with configs?

VPS from Cloudways + WP-Rocket for caching