That's presently what I'm using, but I have added the mull version of the arkenfox user.js via Firefox devtools.

Fennec does release updates a bit slower than mull did via DivestOS's repo, unfortunately, and doesn't have a build up for these CVE's as of yet. Granted, I don't think FF android has these updates yet, but I feel like I remember Mull's updates making it to my device faster than FF's even, as they didn't need to go through external review processes.

Either that or Cromite. Cromite has releases WEEKLY

Yeah, I had similar concerns based on how long Fennec took to be updated to patch a CVE recently (The issue was possibly linked to the fdroid version and might not have applied if I were using Obtainium, I don't remember)

Someone forked and is maintaining Mull: https://gitlab.com/ironfox-oss/IronFox

Will have to see long-term if this is a good option of course, as it's not been long.

Chromium based browsers are more secure but less private on android.

I get a unique fingerprint when I check EFF "cover your tracks" on cromite.