So you recommend flashing the latest ROM rather than a previous version?You can back up most of it with either Xiaomi's or Googles back up services.
Make sure you don't log out of your Xiaomi account on your phone or you'll have to wait another week.
I downloaded the latest ROM version (12.5.9) when I flashed and recently upgraded to 12.5.10 without issues.
There are some safeguards in place to prevent this from going wrong and it's unlikely to go wrong if you flash the appropriate ROM. Whenever it goes wrong it usually involves a custom ROM.
Also, I chose Clean and Unlock in case something did go wrong just to be safe, and relocked the phone afterwards. You probably won't have to do this and just pick Clean and Lock. Just make sure you remember the login to your account.
I have to admit that I didn't try the flash described by Techfreak becasue I remembered that my phone was on a previous version when it came out of the box (I didn't have time to check which version was preinstalled) and it updated to V12.0.8.0 when first turned on.
So, if we flash back to 12.0.1.0 surely the updates will just take us back to 12.0.8.0 again and get stuck again?