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)