Yeah, that’s right @georgie_abitbol.
“microG ready” means that the custom ROM is prepared in source code so that the microG components (Services Core, Services Framework Proxy, Store (FakeStore release) , DroidGuard Helper, UnifiedNlp) can be easily installed later, if useful.
Although mircoG is a useful replacement for the G°°gle Play Services (GPS), it does not fully contribute to privacy and system security. Therefore I can imagine the use of /e/ OS very well without these “mobile services”. I also use GrapheneOS and that works without microG or GPS - with all its limitations.