At (currently) line 316 you have a condition chain checking for whether the planet type is enabled, you method of doing so is string comparison to a hardcoded list of planet themes.
This results in two problems...
Galactic Scale 2 introduces new planet themes, which will cause this hard-coded list to be missing possible theme types; this cannot be fixed via adding more hardcoded themes, as GS2 can add new themes via user-side json.
O(n) string comparisons to match planet theme.
What I would suggest doing instead is maintaining a HashSet<string> that stores all disabled planet theme names, which allows you to simply add or remove themes when they're toggled, and makes the "are we allowed on this planet" check a single line O(1).
Then you can look into how to best autogenerate a setting for each theme (or just use an arbitrary ban list setting) for the GS2 support (if you feel like it).