I found IceRaven mobile browser the closest solution to bringing back features from Fennec. It’s a fork of Fenix developed by volunteers.
Its interface is nearly all based on Fenix but it includes about:config and support for quite a few extensions not on Fenix. I like to think of IceRaven as a proof of concept for Fenix in its ideal form. Some volunteers are proving Fenix can work better for users if Mozilla took the right steps.
The real sticker for me at the moment is real tabbed browsing support. I mean, where is the tab bar if there is no tab? Gah!