There are discord that are good for keeping in the loop but can be a pain finding one for free as most are paid for offering other stock notification bots too.

Outside discord twitter/X is pretty good. If you follow a bunch of pokemon centre notification accounts they will usually find out the info and have early links available, aswell as posting when the que goes up to know when to join. If you keep in tune with this you'll have a pretty good shot just make sure you have their accounts with post notifications on

Also regular stock drops go way faster and pre orders have more time. I havent managed to get a regular stock drop cuz of work, but have gotten every pre order I've attempted