Add cromite (the main bromite fork) which is on Windows and Android, and Mull by DivestOS (like arkenfox for Android). If you want to make a mobile section I would recommend Mull, Cromite, Fenix (fdroid). The thing with privacy browsers is they differ from security centric browsers. Vandium and Mulch are chromium security browsers for Graphene and Divest respectively, Cromite is a privacy chromium browser with good security as well. Ungoogled is designed as a drop in replacement for vanilla Chromium, and has custom flags for hardenning that must be enabled manually.
Maybe Cromite (the main bromite fork) would be better. Vivaldi isn't great, but it also isn't brave. It allows for blocklist importing and user scripts, and is on desktop Windows as well.
Rooting defeats androids security model and allows for further exploitation. Graphene most likely does support it because any AOSP OS that is geared towards security isn't going to leave a big hole in their security allowing malware or bad actors to modify system files (or install a rootkit).