i didn’t, but it is possible, altrough, not straightforward and requires some knowledge. I have an aosp-based custom rom, vanilla InfinityXOS (previously Superior-Extended). I have Poco X3 Pro btw. And because of how bootloader unlocking works, it is not a two-way process on xiaomi devices. Once you unlock it, there is no going back. If you try, it will hard brick and you can get a JTAG or something to reprogram the soc capacitors (doesn’t worth trying, there isn’t any single known xiaomi phone that didn’t brick upon an attempt to relock the bootloader)
it uses snap (less packages and security than flatpak), app.armor (less secure than Selinux), has a history of anti-privacy integrations (like sending user keystrokes to amazon), still collects some user data. Tumbleweed is better. Great kde implementation, strong security, a lot of cutting-edge software, stability, beginner-friendly