pacman -S without update is safe and will just install a version that was in the repos at the time you last dis an update. stuff gets removed from repos after like a month though..
file search in krunner doesn't work without indexing (you have to at least set it to only index file names for that)also, dolphin won't display file metadata (like image resolution) without file content indexing
apparmor is partially supported (check nixos security. apparmor, some manual configuration may be needed), not selinux though and probably never will be
why is vscodium listed separately by the way, it's literally built from exactly the same code as vscode, just without the proprietary licensing, ms branding and using openvsix extension gallery by default
sms is essentialy just a confirmation code delivery protocol tho? (like i have around 100 "chats" with just confirmation codes in them and ZERO conversations...) and i don't see anyone using rcs mostly because of EXTREMELY poor reputation of sms messaging...
or you can allow public authenticated access to dns over https... (just don't expose the raw udp dns server, it's a really bad idea)(not sure if DoT can also support auth, but if it does that's great because android supports dot natively)
you just had to put one of the other fingers on the battery groumd and not push that hard iirc