fastboot is the only way available to flash a rom as for the moment there is no twrp recovery but the ridque is the brick of the phone and it is complicated to recover it
I have the mi 11 pro for 1 short week in ch version and it works very well I just added the fr with more local 2 and I will flash a global rom or xiaomi.eu when the twrp is out because there is a risk of brick