Yes, it's legit. Very importantly it ships microg as a system app, so network location can be used. This doesn't work without a patch or root module otherwise.

Keep in mind you'll only get updates monthly instead of weekly versus LineagOS.

Lastly, this is still Android. You'll just be switching away from the Google-infested Android to one with mostly open source components.

I've used it for last 12 months, works flawlessly and far less hassle

I used it for a while. It worked great.

Thanks for the shoutout - i made note that the OnePlus Nord N10 5G that had support dropped by LineageOS is still supported by LineageOS for microG. Wonder how common this is.

Is legit.

I would recommend installing them separately however because of personal experience but on paper it shouldn't matter.