

That must be Xiaomi’s fault… Android does not do such thing. Check the running processes in Developer Settings to see what’s running that could cause this. After located, disable/uninstall them, with ADB if needed.
Live wallpapers are often a form of ads. Like Motorola have Live Lockscreen, made and owned by Taboola… This is why you should skip bloated Android devices, unless you use a custom rom or don’t mind the extreme debloating.
Glad you like it too!
As for step counters, i personally use a Garmin Instinct 2 Solar (watch). I’m able to use Garmin’s software and that work as intented with my watch. A watch is not for everyone, but it might be worth it to look into some sort of sport/smart watch. As for a standalone app that counts, i really don’t have any suggestions for you. You might like something like Geo Tracker though. It doesn’t count steps (i think), but you can record where you walked, how far you walked and how fast you walked, etc.