LS Server are very fast however the LS Plugin is not the best. I compared many websites (cloned) with LS Server and LS Cache vs. LS Server and wp-rocket. The result is, that wp rocket cached sites are at least the same fast, often even faster in fcp and full loading time.
I dont know the background how LS is working but i am sure there is a possibility to optimize wp rocket cache with LS Server, because add ons for e.g. varnish are already exists.
My wish for 2022 :)