Installing Volla on Volla Phone X23 (Gigaset GX4 PRO) - Which UBports version to use now?

I understand that later versions of UBports installer such as 0.10 and 0.11.2 have had problems such as: Volla not flashing to slot A: "Unknown Error while flashing Volla OS to Volla Phone X23 #4385" I know that developers on Github have provided a configuration file to fix this but I would not know how to apply this file to the installer. A later version of Volla which would be incompatible with Halium 12 if the phone is running Android 12. Would it be better to use version 0.8 or 0.9 of the Ubports Installer in order to get Volla 12.1 installed sucessfully?

I have never flashed a ROM unto a phone before.

My laptop is running LMDE 6 so it would be done using a Linux system.

I would appreciate any advice.