Hello i found that:
Widewine L1 certification is required to play drm content from providers like netflix and hotstar in hd, its currently enabled in current miui beta and with soon be available for stable miui, for enabling L1 in custom roms U with TWRP installed follow these steps.
1. Download latest miui rom from xiaomi.eu
2. Backup all partitions in twrp
3. Clear data, system,cache,dalvik in twrp and flash xiaomi eu rom
4. Boot in xiaomi.eu rom and skip the initial setup of signin, if black screen apppears then reboot, connect to any wifi network and then try again
5. Setup fingerprint
6. After setup go to settings and fingerprint u will find the option of widewine L1 ,click update certificate & done!, To cross check download drm info app from browser to check the certification level
.
Done! U can reflash all partitions of all your backup in twrp now, your certification is permanent
Eu roms dont have encryption, but if u want to be safe u can flash disable forced encryption zip
from xda
https://forum.xda-developers.com/poco-f1/how-to/widewine-l1-custom-rom-t3904600
maybe someone wants to test.