dreamy

Here is an overview of all audits done on Signal:
https://community.signalusers.org/t/overview-of-third-party-security-audits/13243
No recent server audits really. They are pretty public about information requests made by the government and their responses though, and from what I can see the only pieces of information they have shared with the government to this point are the time of account creation and the date of the last connection to Signal servers:

You can check more of their responses from here:
https://signal.org/bigbrother/

vis. Only used it for editing configs and stuff though, not programming.

I’m on Artix Linux and it did automatically create it after an update.

It likely just runs xdg-user-dirs-update which, in my experience, doesn’t delete anything if the folder is already there (the command just changed the folder icon in the file manager when I used to run it on a WM).

You can install Aurora Store and use that instead of Play Store. Though be aware that disabling/removing Play Store may cause issues with some apps that require Google Play Services for some reason and those apps don’t have to be completely proprietary for this requirement (Stoat’s mobile app doesn’t launch at all without Play Store for example).

I would also recommend disabling background connections and running in the background for proprietary apps you install. I’m not sure how you can do this on Samsung but this is how I do it on Xiaomi:
Running in the background: App info -> Power -> Select “Restrict background apps”
Background connections: App info -> Network access -> Disable “Background data”