what is the main problem this snap thing is looking to address ?
Third party software developers wanting to push their latest software releases directly to users, and for users wanting to install such software.
For users who are happy to use the traditional distribution-curated model, getting all "feature" software updates when doing a distribution release upgrade only, snaps are not necessary and you can use Ubuntu 20.04 perfectly fine, as normal, without using snaps.
As others have pointed out, Chromium is no longer packaged as a deb. You can use Firefox, or get Chromium from another source. An AppImage is available for example. I haven't tried it, but it should be functionally equivalent to using a distribution deb.
Or use Google's Chrome deb, for example.