I’d be really grateful for recommendations for a good sling for our 3 week old. We have a Boba wrap but my DH is keen for something a bit more structured and easy to put on and take off. Thanks in advance.
A stretchy wrap (like your Boba) really is the best for now. Babies need something soft that holds them close without too much padding or hard plastic in the way. Your dh is probably best to just do lots of practice and get more comfortable using it in the immediate term.
A bit longer term, something like an Ergo or a Manduca would be great (no a Baby Bjorn), but personally I wouldn't bother before baby is about 2-3 months old as they really aren't especially comfortable early on with a small baby. Go to a sling meet though and hire one to start and have him get some practice trying it on and finding the right fit, especially if he'll be the one using it lots. We have an Ergo and my dh loved it and we used it until our dd was probably 3 ish? But it's not quite as comfy as a stretchy wrap and they are more expensive, so you'll want to know it's right for both of you before you commit.