I know that there are budget considerations, but this is HBO Max and money should be less of a factor.
Less of a factor than for network TV, but more of a factor than for a tentpole feature film. I certainly wouldn't object to seeing a more space-based GL series, but I wouldn't be surprised if it were more Earthbound. Even a space-based show would probably have some concessions to budget, like having permanent standing sets (maybe a hero ship like in Green Lantern: The Animated Series), infrequent use of non-humanoid GLs, or the like.