We did some work recently to resurrect the translation infrastructure, which was completely dead from 2015-2021. In particular, we added the possibility to translate strings in HTML documents.
However, we still don't have the actual pipeline for translation contributions set up. If you have any experience with translation software, it would be nice to hear your recommendations on what we should use.
Imo Weblate is the best platform for open source projects. I.e. Kodi switched from Transifex to Weblate in 2021. Transifex is quite outdated in terms of integrity with GIT. Another interesting platform is Crowdin.