for chromium I am actually using the Linux Mint packages (which work absolutely fine), and I have just set up a small repository I can add to apt:
deb [arch=amd64 allow-insecure=yes] http://snapless.cmeerw.net victoria upstream
this just syncs from Linux Mint and only republishes chromium in the Packages file (with downloads redirected to a Linux Mint mirror). BTW, I am not signing these...