since xiaomi.eu is sourced from china miui rom (just debloated) the version wont be updated anymore. my redmi note 4x is running on miui10 (android 7) i think thats the final xiaomi.eu rom you can get for this device. so yes netflix and some other banking app like mae wont work on this device.
it's under EOL (End of Life) Devices in xiaomi.eu website already. if you want to use banking apps i suggest you just change to latest budget devices.
if you want to install custom rom you can check xda, but you need to know how to tinker with the device if you want your banking apps to work.

if you run lineageos or other custom rom except xiaomi.eu, unless you use install root with magisk and use magisk hide it will detect custom rom and wont run i think. if you use xiaomi.eu they can pass safety net hence banking apps and such is allowed to use. but problem is the version is too low. so you can look into install android 10 custom rom and magisk hide if you want to use banking apps.