#criticizing that they've had a paltry set of add-ons and built in translation for years

[zoobus]

Genuinely curious, how does mobile Firefox prevent using extensions in their full capacity?

Firefox Mobile only allows add-ons from a short list of extensions that has barely lengthened since it came out years ago. There's little variety in their selections either, so you can expect any new additions to focus on functionality (eg google search fixer), cybersecurity (anti-trackers, adblockers, xss protection), and productivity (pomodero). That's great and all, and yes I understand their aversion to introducing potential vulnerabilities, but I use my phone more than desktop and I will accept risk to make things easier.

Firefox Nightly allows custom add-ons, but I found it too unstable to use as a primary browser.

Fennec and Mull are both Firefox forks that allow custom add-ons and are updated often, with Mull the more hardened one. I don't actually remember why I chose IceRaven over them.