Unless you are Chinese user, which means you are double fucked.

To unlock your phone, you need to:

1. Level 5 Xiaomi Forum Level (Gonna take half a year if you only check in daily, if you post and replies, then its tiny bit faster.)
2. Make an appointment for the Unlocking Permission Test (random dates, xiaomi is also slowly/quietly limiting the number of test dates)
3. Pass the test (timed, broad range/difficult technical questions, akin to a 300 level college exam that you're not given any materials to study for)
4. If you pass, you're only allow to unlock 3 phones per year.

But hey, if you bought the phone outside of China (or simply not Chinese version), then you don't have to do any of those except wait for 68 hours. Fuck the Chinese users eh (Chinese version also has a lot more bloatwares, the apps that you download from xiaomi app store also more invasive (more permission) than google play versions).

I think it's 72h after linking your phone to your Xiaomi account, don't need their pc app abd tools work fine.

It's still one of the brands that are most open for custom roms since you'll retain your warranty unless you manage to do physical damage to the phone in the process.