Went with lineage since I grew up on cyanogenmod.

For me LineageOS is a good baseline. I don't have anything against "privacy" OS's but they're not really for me. I just use F-Droid to get apps and don't care about compatibility with proprietary stuff so neither microG nor the GrapheneOS sandboxed Play services are of interest to me. I don't use GrapheneOS because I don't have or want a Pixel phone.

LineageOS significantly increases the lifespan of devices it supports and that's important to me. Planned obsolescence is cancer.

My ideal mobile OS would be something like Mobian (or even better, a GNU Guix based distribution) but it should be noted that AOSP is also a Linux based operating system and thus anything derived from that is a Linux mobile OS.

Btw, is there a stripped down from AOSP custom rom around? I only want to use my old phone as alarm clock but standby holds only a week, despite the battery being rather big. My old Galaxy S3 with custom rom and BBS optimized held a month at least.

PureOS

grapheneos on a secondhand pixel 5 which was about 280$AUD. though i probably should have gotten a newer model considering the 5 is nearing end of life for GOS

GrapheneOS as well with profiles

Been using /e/OS on a OnePlus 6T for the last ~2 years and love it. The built-in ad tracker blocker works well. GoS works for the best part and if it doesnt, heading over to the website usually works.

I put lineageos on my old OnePlus, which had started to lag so much that even the password prompt would take a minute to register my key presses. The moment I put lineage on it, it started working as if it was new and finally had security updates for the first time in 2 or so years. I now use it as a backup device, and also as a webcam for my pc using scrcpy.

Graphene OS users, what options are available for backing up your phone? I tried looking for an answer but wasn't able to find anything recent on this topic.

I want to try it but this is the one thing holding me back.

Crdroid with microg is what I use Getting rid of google services altogether is a huge mess. Its hard for me tbh. Lineages for microg (lineageos4microg) is also something that I wanna checkout. Grapheneos is fine only if you want to pay for it.