I found MIUI ok. They take away a couple of useful features, like the one that lets you keep your phone unlocked at home.
How's the in-screen fingerprint reader on the Poco? The Xiaomi P9 in-screen fingerprint reader was so bad I sold the phone a few weeks after I bought it. I miss the performance and cameras of that phone, but unlocking it was a real PITA for me.
Xiaomi hardware with a rear fingerprint sensor and Android One, ideally with a smaller screen, would be fantastic.