Does rebranding apps make more work?

hello eelo community !
i’am testing eelo on old nexus 5 !
I found Dav/droid that i used to install on my phone without google account and connect to my mail server with SOGo cal/dav services.
So We found K9 fork for mail app. best of one

I think that the objective is to supply a turnkey, " ready to use " solution the free maximum and without service to “privateur” behind.

So does you will rebrand all f-droid for your own or it will be comptabile ?