In "Gpu Setting" the frame rate slider, texture quality...etc options are not working in miui Eu14 stable/weekly...
Whereas No such issue on that of china build.
Actually you can update system apps EU.
It's just devs who doesn't want users to use third party apps to forcefully update system app because it's a bit risky if you update core system apps. And it might also cause issues for the next miui updates.
Here's the screenshot of my joyose app. After updating it, gpu tuner finally works but editing GPU settings will be locked per app even gaming mode is off but it's fine since you can still set it back to default.
I used third party app to update system apps, search it from YouTube for reference. I can't give it here cause it seems that it's not a supported option from devs and i respect them a lot.
Use it on you own risk. Don't blame anyone.