I need a fresh "restart" with my mi11pro - who can help?

[messy]

hello guys,
I am new here, looking for help. what happened:
I've have imported a mi11pro, everything was ok. then upgraded to the next stable rom via OTA, worked fine.
i got a new car, tried android auto. shortly after that, from this point on my WLAN went offline regulary. no chance to bring it back on, only with a restart until it breaks again.
then I upgraded to the weekly rom, currently V14.0.23.1.3DEV/beta
It worked fine, also the WLAN. after connecting again via android auto, same problem: WLAN stops after a short time. so android auto seems to be a killer for my wlan chip, i don't know why. I tried to reinstall the V14.0.23.1.3 dev weekly with the update package, but the installation stops with errors. I have also updated to TWRP 3.7.0.12-Mi11Pro_v6.6_A13

now I want to do a fresh restart. total deletion of everything, new kernel and a stable rom. what's the best way to do so? My problem is, that I don't know if I just can use the installed TWRP version to flash a new ROM, or should I use fastboot (and if, how does this work ??) and so on.
thank you for your help and I promise, I won't use android auto again
Messy

 

[Imzadi]

I just did it like this:

Clean install

I want to perform a clean install on my Mi 9T Pro (meaning that I want a brand new phone, no pics, no data, nothing from the previous install), what should I wipe from TWRP? I've read that I should not wipe System and Persist in any case, but can't I then copy the rom .zip via USB to the...

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