It is a snap permissions issue. With the Snap 2.70+ change, snap-confine no longer needs to be setuid root , and instead relies on file capabilities , executing in the security context of the invoking user .​

You can follow the step below to install Chromium using FlatPak.​
#1.Uninstall it from snap then begin.​
sudo snap remove chromium​
#2.To install FlatPak​
sudo apt update​
sudo apt install flatpak​
flatpak remote-add --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo​
#3. Reboot your machine, then run the following command:​
flatpak install flathub org.chromium.Chromium