Firefox on desktop and Mobile. To keep browser monopoly away. All settings set to max strictness except no DNS, because I have a VPN. Firefox works on 99.9% of sites. You can use a script called Arkenfox, to harden FF even more, almost to Librewolf, but with the advantage of updates coming directly from mozilla. I love the sync function across FF, so that’s why I have it on my mobile as well, it’s seemless.
I thought CopperheadOS was just the former name for GrapheneOS? At least that’s how I understood the statement on their page.