Is it so hard to read first two posts?
It is a breake for all phones, your redmi pro is not speciall. Just few most bugged (Oreo) phones recive bugfix versions until some day in June.
I wouldn't say it is stronger. Snap 820vs821 is not a big difference. Also they both have 3 and 4gb ram versions. The are very similar just Mi5 has this advantage that it is main model in this line. That's why it has faster updates.
I skipped 8.5.17 so I can't say. Overall it seem to works well.
Just flashed, all fine so far. It looks like the animations are a bit faster. But to more detailed review more time is needed.
Please check here:
https://xiaomi.eu/community/threads/global-rom-notification-style-port-for-xiaomi-eu-china-rom-developer-stable.43151/
However keep in mind that it may be not compatible with Oreo roms.