Chroot Debian on my Redmi Note 11s running LineageOS. I built a USB keyboard case for it almost 2 years ago and have been daily driving it as a palmtop ever since.
It was the push I needed to start building my dream device. They say Linux phones aren't ready, and they aren't. But the Linux desktop on aarch64 has come a long way thanks to things like the Raspberry Pi so I'm currently working on a Mobian pocket laptop that can replace my phone entirely. You can find a Pixel 3a XL for around $100 with an unlockable bootloader, just don't expect a usable camera. Currently the tradeoff is either freedom of software with some missing drivers (USB host mode in particular) or using a distro like Droidian or UBports which is custom built to run on Halium and the android kernel and can't be easily modified/tinkered with.
Chroot Debian on my Redmi Note 11s running LineageOS. I built a USB keyboard case for it almost 2 years ago and have been daily driving it as a palmtop ever since.