This world was created yesterday in 21w13a.
I did some debugging and there is a missing directory /opt/minecraft-launcher/swiftshader/ that should contain two symlinks: libGLESv2.so and libEGL.so.
After creating the directory and a symlink to for each of these files, the skins tab in the launcher starts working.
Unable to upload launcher_log.txt. Reinstalled old deb file before saving the launcher_log.txt file.
Ran 'apt remove minecraft-launcher --purge' before reinstalling latest deb file. Subsequent runs of minecraft-launcher work normally.
This ticket was created about two months ago and the game is currently in Release Candidate 1. I loaded up the latest pre-release and preview datapack and made a short video.
I can't tell whether the problem is still present or improved or not. Generally when I play I build a 9x9 structure as my starting base and dig down from there. Each new level excavated is a 7x7 area, and I seem to not hit any iron ore even after digging down to level 0 or lower (this world in the video does not appear to have generated below Y0. The past few worlds I've created I've come up short on iron after mining stacks upon stacks of copper.