I had a similar roadblock switching fr GL firmware 3.216 to 4.4.0.
Flint v1 GL firmware runs on OWRT 21.0x. v2 is on 23.05. Some differences in configuration is expected but nothing that can’t be replicated. You can use 7zip to cherry pick the confs fr the Flint v1 over to v2.
By default all files in the tarball are just text files anyways.