On a Xiaomi device myself. Recently I've setup Nextdns.io to resolve all the DNS requests through it. Very frequent callbacks to Xiaomi servers for tracking. Blocked a bunch of them now, but it's half a solution.
I have a tissot with LineageOS 16.0, not sure yet whether it will get 17 ported to it as well. The hardware is great for the price (bought it a year after launch, heavily discounted). I bought it specifically to run LineageOS on it, so I have no idea what the stock experience is like.
Running it for 2 years now.
The bootloader is locked by default but if you ask for it to be unlocked they will do it. The process is intentionally manual to prevent hacking, but ultimately smooth.
Not only you need a Windows computer to unlock, but then it takes literally months to proceed and if you happen to do something that you're not told you should not do (like logging out or re-trying to unlock), the counter is reset and you have to wait even more. Plus the unlocking program on Windows randomly doesn't work and error messages are not helpful at all.
My Xiaomi is an impressive, nice and powerful phone that hasn't cost much. But it was so much pain to root that I won't probably ever buy a phone from them in the future.
I'm using a Xiaomi with Android One and despite having opted out of analytics the phone still tries to connect to Xiaomi servers.
I've been considering installing LineageOS on it for some time but unlocking the bootloader unfortunately deletes everything I have installed or downloaded. I've never used the stock browser though, always Firefox.
[1] https://raw.githubusercontent.com/jerryn70/GoodbyeAds/master...
[2] app.chat.global.xiaomi.net
It would've been a good opportunity to allow people to install whatever they want, to show that they're different than Samsung and other competitors, but no, they went and locked that down because of "safety". Mhmmm.
It's gross.