I don't really see the benefit in this. You can install LineageOS without gapps and MicroG already distributes a fork of LineageOS that includes MicroG. If you want full control of your device you will likely be better off going with something like Librem 5 from Purism.
Edit: getting downvoted so for clarity this is the part of your comment I'm referring to: MicroG already distributes a fork of LineageOS that includes MicroG