I was under the impression Flatpaks are sandboxed. (I am not an expert.)
Flatpak is a utility for software deployment and package management for Linux. It provides a sandbox environment in which users can run application software in (partial) isolation from the rest of the system.
I was under the impression Flatpaks are sandboxed. (I am not an expert.)
I also keep Ungoogled Chromium around as a last resort (AppImage in my case).
Flatpaks are as sandboxed as the sandbox settings you give them, check out if the defaults are satisfactory on Flatseal before running it.
Flatpak is not a sandbox
https://hanako.codeberg.page/