I've found success installing Steam and other stuff using distrobox on openSUSE Kalpa. The initial setup isn't as easy as installing a flatpak, but after a quick distrobox-export it's totally seamless.

... are you ok?

Only 5 of the bullets are related to privacy. The first two regard Apple's purported plans to implement client-side scanning, which have been paused and and don't presently exist. The third one was FUD that has been debunked. The fourth one has a broken link. The last one regards Apples tracking of iCloud account usage in their apps and services, which is totally optional at least on macOS.

There are plenty of reasons to avoid Apple, and this page lists several, but the privacy argument is not strong here.

LibreWolf has an official Flatpak, which is great for Linux users. The Mullvad Browser Flatpak is not official and allegedly makes suspicious connections.

LibreWolf has good private default settings, but the Mullvad Browser and Tor Browser can go the extra mile because they're meant to blend into a crowd, through VPN traffic and the Tor Network respectively. If you plan to log-in to sites, install extensions, enable uBlock Origin lists, or customize your browser at all, you defeat the purpose of those browsers.

LibreWolf by comparison is far more reasonable to customize. They even have a custom settings page for the more intense privacy settings among other things. Enabling persistent storage for sites you log into is easier because it's not forced into Private Browsing all the time. These changes are reasonable because the goal is not to blend into a specific crowd.

There's no reason you can't use all these browsers (and more) if their use cases sound relevant to you. I use LibreWolf, Mullvad, Tor, Brave, Vanadium, Mull, and even Edge depending on my needs.