The way I did everything to Nokia TA-1053
Stock Android 7
Updated to Android 9
Downgraded to Android 7 (for bootloader unlocking)
Upgraded to Android 9 (after unlocking)
Flashed twrp (shitty thing I’ve ever done)
Rooted with magisk.
If your stock recovery is overwritten, sadly, you cannot install any OTA. Can’t you do ever? Well, yes you can. But, you have to;
Downgrade to Stock (7.1)
Unlock bootloader (if needed)
Install all available OTA to Android 9 including July security patch
Flash Magisk (if needed)
I don’t think HMD Global will rollout Android 10 for us. Security patch will be okay. Again, if you are going to flash twrp , make sure to backup your stock recovery before messing. It means a lot! If you’re using Linux like me, use Heimdall.