I first started playing Violet a month and a half ago. A couple weeks into playing my wife expressed interest in playing too. So I got a copy of Scarlet for her. Since I was so far ahead of her (both in the actual game and knowledge of the games, I have been playing since LG/FR, while she has only played GO) I decided to take a break from Violet to finally play Shield. I purchased it when it came out but never left the starting town.
I have now beaten Shield and use the raids there to level my Pokémon in Violet. In Violet I have beaten all of the gyms, all of the Titans, and just have 1 more Star Base. When trying to join a Tera raid I can only join random ones, the ones on be board always say I failed to join. But doing the random raids I end up with so many 1*-3*s. When I am looking for raids I am having the same issue, they are all lower.
Even before I became the champion in Shield it was faster to level by transferring my Pokémon.
Interesting, I found it to be the opposite for me. It’s incredibly tedious for me in Shield, but in Violet since I can send my pokemon out with R and just keep attacking wild pokemon without entering battle, it made grinding a lot easier for me. As a bonus, you get to farm pokemon materials for TMs.
I will say that raiding in Violet got worse after the DLC came out. There was definitely too many people hosting 1-3 star raids when they’re easy to do solo, but I admit I was definitely one of those people too when I first started playing.