Update #3 [Thu 27th Apr, 2023 04:30 BST]:
Pokémon Scarlet & Violet Global Challenge 2023 III has been announced - giving trainers the chance to get their hands on an Ultra Ball Canvas Backpack.
Registration is open from 27th April until 4th May, and the battles will begin on 5th May and run until 7th May. If you participate in three or more battles, you'll receive this special item as a code via Pokémon HOME.
Update #2 [Tue 25th Apr, 2023 03:00 BST]:
If you participated in the Global Challenge 2023 II event on the weekend, you should now be able to claim this serial code for a Great Ball Canvas Backpack in the mobile version of Pokémon HOME.
Original article [Thu 13th Apr, 2023 05:05 BST]:
Since the arrival of Pokémon Scarlet & Violet late last year, the limited-time events and promotions in the game have been non-stop. The next one coming up is the 'Global Challenge 2023 II' (the second phase of the Global Challenge 2023 competition).
Serebii.net notes how registration is open from 13th April until 20th April, and battles will run from 21st April until 23rd April. Participants will receive 10,000 League Points, and a 'Great Ball Canvas Backpack' for all players connected to Pokémon HOME that participate in three or more battles. Codes for the backpack will be distributed to HOME after the conclusion of the comp.
Here's another look at this cosmetic reward, which follows the Poké Ball Canvas Backpack distributed in the first round.
Although this event is tied to Pokémon HOME, there's actually no support for this Switch app just yet. A previous update dating back to February said Violet and Scarlet would receive Home support in "early" 2023. The app recently got an update to support S&V online competition data.