Shameless plug (sorry) but I’m working on one too! It’s a web app that works on both desktop and mobile: https://slemmy.libdb.so.
It is a free-time kind of project (I work on it after my actual working hours), so it might not grow at the same pace as other newer apps, but I’m trying!
Source code is at https://libdb.so/slemmy, AGPLv3 license.
I’m adding this into my Lemmy client’s README.