Hi! I'm new to this metagame (and OM in general honestly)
But this one looked really fun
My first attempt is building a Sand Team
The main thing I went out of my way to do is to run double sand setters. Running one, you frequently run into the issue where you have to guess whether your opponent will call your bluff and send Politoed in T1, or if they'll respect that you have a slower setter, and put something else in turn 1. With two setters, you can always ensure you get sand up while forcing their setter out, and you don't have to give anything up for it in this metagame!
Also, Heracross looks really weird in this team (still deciding how I feel about it), but I feel that Hera in general is very good in this OM, having an amazing suite of abilities (Guts/Moxie/Swarm), allowing it to shred teams with Guts+Swarm Boosted Megahorns, or extend its own longevity with Resttalk Facade Megahorn sets that still do chunks. Sand aids the offensive set by speeding it towards Swarm range, and isn't as scary to the defensive sets because you're almost always asleep (Sand also means that you don't have to worry about being full HP and unable to go to sleep when you need it)
Other than that, I think this team is fairly standard:
Gastrodon is a must on Sand imo, is an amazing bandaid to help the rain matchup (as well as other sand teams, and being one of the few dracozolt answers)
This mon is straight up broken in this format IMO, outspeeds most of the metagame in sand, and that plus a Banded Bolt Beak* (Hustle permitting) is enough to ohko a massive portion on the metagame, and 2hko the rest. It also has options like Outrage to hit grounds, and Fire Fang/EQ to hit steels.
I think I'll try building Hail next, but I just wanted to post to say thanks for this amazing OM, and I've been having a blast!
*Thanks for pointing that out, I read it over four times and missed it every single time ;-;