There should be a category for all regions, going until you finish galar. When you click on the next region in the region selection menu, timing stops until you pick your starter. this is to give the player time to rest, or get food. this is good because the later regions take a lot longer and are more tedious. rules would have to be added about things happening during the break (berries growing, mining energy replenishing). I think this would be a fun category to add.
Sorry for such a late reply to this! I agree that it could be interesting, however the length of time it would take to get to Galar and submit a run would make this likely unappealing towards the general community. That being said, if you or anybody else do a run of it, we can look into adding a category for it retroactively to allow the run to be on the board! ~Shine