There is an ongoing discussion about this in a thread on the Swedroid forum.
No clear solution has appeared yet.
In short, your device does use some data traffic without your consent...
I don"t use the built-in camera app at all usually, though it has worked when I tried it.
I use rather 2 different G -cam apps and Open Camera.
None of these work perfectly in all situations, especially slow motion does not work.
The G -cam apps often just crash.
But they take much...
I can recommend the no-root firewall Netguard.
Available on Playstore and GitHub.
It's really good, but of course if you need something that only works with root, it cannot do it.
Xiaomi.eu released the stable v126.96.36.199 for Mix1 (lithium) on Nov. 8.
Normally it should have been released for Mi Note 2 at about the same time.
The official China stable 188.8.131.52 is available.
So I suppose there is some kind of problem.
Mi Mix1 somewhat unexpectedly just got the last stable eu V184.108.40.206, so I would suppose it should appear any day now for the Mi Note 2, as they are closely related.
The official Chinese 11.0 2.0 is available at least.
I'm staying on eu weekly 9.10.10 personally, just keeping track.
You might try the last EU weekly 9.10.10.
In my experience a good weekly is better than any monthly.
The only other alternative seems to be LineageOS.
Note 2 is still officially supported on Lin.OS v16, with nightly(!) builds - but automatically generated.
I have never tried it.
But there is...
Install the Mi Router app in your mobile phone, and connect it with the router.
In the Mi Router app there are settings for Samba access (to the disk on the usb) for each connected device, you have to enable each device separately.
One can always migrate to LineageOS 16, Android 9, which currently is supporting automatic nightly(!) builds for the Note 2:
I figure on staying on the last really good weekly, this one 9.10.10 is a candidate if no serious bugs appear.
Xiaomi will probably eventually release a final stable for these devices, but I would not count on it being very good, and Xiaomi.eu may not do it - that is what happened with the Max1...
It means of course that all these Android 8.x devices will jump right over 9.x and get android 10 directly!
For this Xiaomi will be sending out free motherboard upgrades with sd 855+!
Or what did you expect?
Installed EU 9.9.26, running fine, no problems so far.
Baseband, kernel, and security patch versions unchanged since EU 9.8 29.
Inkypen on XDA made yet another new TWRP version.
I have not tried it, still using the last raupe-blunden TWRP.
Perhaps you need it if you want to run a Android 9...