Preferably nothing should be allowed imo. Shop accounts are very minor if you ask me, but still gains you an unfair advantage to regular players, although as small as it may be. But I assume they need some leeway so they don’t need to investigate everyone playing from home with a sibling or family member.
Best case scenario would be if they would start designing the game to be less alt account friendly. Saalus is not fun. It’s just a forced bullshit thing you have to do because the rewards are good. Events shouldn’t give tradable items even if it’s “fun”, because it’s just plain abusable. Especially considering how incredibly difficult it is to get recipes from actually doing raids, compared to just making a bunch of accounts and doing no effort events for asio/wastrel recipe boxes. It’s just stupid.