I think adding more language is very important to really be usable, as most of us want to bridge to Asian languages, thus Japanese, Chinese, Vietnamese, Korean... should be our priority next.
@Terax, Floorp does support Tab Group, and for people who want both Tab Group, use Floorp, this is full guide: https://github.com/Floorp-Projects/Floorp/discussions/876
I think Mozilla devs, please consider seriously about adding Tab Group, it's a high time for us to have Tab Group because Chrome users are switching to Firefox, but the lack of Tab Group is making them go back. We can't waste another oppotunity, back...