Regarding the OnePlus Nord 2:

To work well, GCam needs a Snapdragon processor. The Nord 2 uses MediaTek.

AVOID MediaTek if you want to use GCam mods.

(This applies to all brands)

ℹ️ The new GCam 8 from Arnova8G2 supports configs like before, but on top of .xml files, it also supports/saves .gca files.

Nothing changes for users in practice, but .gca files contain more than just settings inside (eg: better settings and a lib). It's like a .zip file.

.gca files are saved in a different folder:

.GCA files: /GCam/GcaFiles/
.XML files: /GCam/Configs8/

To load .GCA files:

Settings » Advanced » XML Config » Load » Select config

I have created a new configs page for this new version:
https://www.celsoazevedo.com/files/android/google-camera/f/configs-arnova-09/