What stock ROM do you have have?what version and is It EU or,..,?Sorry to bother, read on Sakura faqs:
Following your guide above, once unlock the bootloader and installed twrp, and wipe dalvik, cache, vendor and data, i'm a bit lost about installing firmware and vendor zips, you do not mention above about these modules, are these necessary before installing the Sakura Rom?
I found them here:
The ultimate script that provides firmware packages for Xiaomi devices.xiaomifirmwareupdater.com
On this website there are 3 downloads fro the 10T lite, firmware, vendor and MIUI:
1) Redmi Note 9 Pro 5G/Mi 10T Lite/Mi 10i gauguin stable V126.96.36.199.RJSEUXM 11.0 Europe Download 2021-05-27
2) Redmi Note 9 Pro 5G/Mi 10T Lite/Mi 10i stable V188.8.131.52.QJSEUXM Europe GitHub | SF 1.3 GB 2020-10-0
Need to install these two files (discarding the MIUI) via twrp before or i can flash directly the Sakura rom?
Read here on xda that majority of last custom roms have already inside these two modules when flashing a phone, but i'm confused since the installation guide mention that i need to do this myself.