Yes, it is. Stable miui v9.6.4 doesn't support fingerprint, and the latest stable version 10.3.2 does.
Great!
Seems it's just the firmware partition that is needed however, as I mentioned. (This is also updated by stock ROMs.)
Strange you had MIUI 9, I thought plus version shipped with 10, and later firmware. (See gsmarena)
And as I said in post I linked (
https://forum.xda-developers.com/mi-pad-4/development/rom-lineageos-17-0-t3989187/post82638183 see Other Partitions), while weekly (developer) build versions cause confusion, files from weekly ROM listed as '9.8.29' are actually the latest for MiPad4. This version is actually v10.5, so later than Stable ROM 'V10.3.2.0.ODJCNXM'. ('Updated' date is best indication of comparative age here.)
Latest China Stable, version 10.3.2.0, was released 2019-05-24, whereas latest China Developer ROM, build date 9.8.29 (ie 2019-08-29, not version), was released 2019-09-02, making it 3 months newer.
So if you simply flashed latest stable ROM you still won't have latest firmware. To check (on LTE models), find baseband version in Settings, About tablet, Android version in LOS. Baseband should be 660_GEN_PACK-1.214729.1.215613.1 (with 9.8.29 weekly developer firmware)
If you don't have latest, you probably should flash the firmware from weekly developer ROM as users here have reported other problems with Android 10 ROMs including LTE / call problems.
Mi Pad 4 got updated from MIUI 9 to 10, but all stock MIUI have had Oreo (8.1) base.
Further, it appears Xiaomi were developing for possible Pie or Quince Tart

releases (with updated commits in developer ROMs and firmware) before abandoning development for MiPad4, which would explain why 10.3.2 firmware was fine for latest MIUI (Orio), but 9.8.29 (10.5) firmware is needed for our LOS 17.2 (Quince Tart).
Nb. You no longer need to reinstall MIUI stock ROM. Go to
https://xiaomifirmwareupdater.com/ and select just Firmware from menu button under 'downloads', put "Mi Pad 4" in search box (spaces needed), download and flash. (Vendor files and Full ROMs - recovery and fastboot types - are also available here). PW
I've never updated the firmware. Where do I tell what version is installed currently?
Hope the above answers this too.
Nb, if you don't have an LTE model you can't see baseband version in settings, and I'm not aware of other ways to determine firmware version loaded.
If you've never updated to a developer MIUI release ROM or firmware however, it's safe to say you don't have the firmware with the latest commits. PW