Launcher doesn't work anymore on Linux after update (liblauncher.so: LoadErrorNotPresent)

just now started the launcher, it downloaded and installed update files, and now it won’t start anymore. when run from the terminal, the only output is:

https://launchermeta.mojang.com/v1/products/launcher/6f083b80d5e6fabbc4236f81d0d8f8a350c665a9/linux.json
MessageBox(Minecraft Launcher): Couldn't load launcher core from /home/[username]/.minecraft/launcher/liblauncher.so: LoadErrorNotPresent

(the file liblauncher.so exists at that path and its timestamp fits the update procedure)

the date on launcher_log.txt gets updated, but file content remains old. (CORRECTION: the logfile indeed gets updated and shows the error pointed out by brian carlson below.) launcher_cef_log.txt remains untouched.

tried: downloaded minecraft.deb (version 928) and installed it. didn’t change anything.

uninstalled the minecraft launcher, renamed ~/.minecraft, reinstalled. same effect.