as a feedback: i9100, MIUI 11.2.9 working. no issues with themes. What I did was:
- start line: miui 2.10.26, control panel 2.10.26, lang package ITA for 2.10.26 (please note: I had a mixed theme applied: black android, plus a couple of others for sms and dialer)
- [from recovery] dalvik cache wipe, rom flashed and system reboot
- reboot in recovery (3 buttons procedure), flashed appropriate control panel and system reboot
- reboot in recovery, flashed appropriate lang package and system reboot.
Everything ok. GApps still in place.
When I opened themes app by the first time I saw a "themes update" (it took 4-5 minutes, it "updated" 39 files), then I tried to change themes (or part of current theme): no issues.
Only prob I have is that I got 2 new apps: Voice Assist and what I guess is a sort of player. Both have chinese text or voice. The rest is ok.
cheers