I'm a custom ROM developer that spans a lot of devices (TrebleDroid GSI, a generic kind of custom ROM that works on thousands of Android devices) I've bought dozens of smartphones to implement bug fixes (current total number is 50).<p>I used to buy Xiaomi devices, because there are a lot of users (lots of bugs to fix), and often have brand new SoC at affordable price early. But I've stopped buying Xiaomi for a few years now, because of the low reliability, high complexity of Xiaomi's bootloader unlock, and the rules keep changing.<p>So far it looks like the community of people using Xiaomi devices with custom ROM is still pretty strong, so it's not necessarily a bad idea to buy Xiaomi. But I very strongly recommend that you unlock bootloader right after buying your device [1], because buying a device now and expecting to be able to unlock it in 4 years look too optimistic to me.<p>[1] Though you'll most likely won't be able to "just" unlock and forget it, because of all the apps that really really really want you to run Xiaomi and Google adwares and not your own OS