No readable text in file selection popup Opera browser on Ubuntu 20.04 [duplicate]
I found the solution, was more simple than I thought.
First, you need to update local cache as described here:
rm -rf ~/.cache/fontconfig
sudo fc-cache -r -v
Then, you need to find fontconfig folder inside snap, since this is the snap version of chromium.
find ~/snap/chromium/ -name 'fontconfig'
Last, remove this folder inside .cache:
rm -rf ~/snap/chromium/common/.cache/fontconfig/
Afterwards, chromium will recreate this folder automatically by using your local updated fontconfig inside ~/.cache/fontconfig.
Restart chromium browser to take this effect.