I used App Manager (io.github.muntashirakon.AppManager) for the screenshot; you can use your regular 'Installed Apps'/'Apps' menu to see if it's been rolled out automatically for you as well.
edit: First link was originally a typo, my bad. Fixed it.
At this time it is currently better to go with a custom Android ROM. Linux phones are currently have almost 0 security. I say almost 0 because postmarketos does support LUKS encryption, but only on some devices, and pmos uses an "upstream kernel" update model for devices, so a lot of the drivers for supported phones are not fully complete.
None of them have sandboxing, or measured boot, and excluding postmarketos, none of them get driver level security updates either.