We got the little life backpack that converts into a toddler carrier. It’s perfect for days when they are up and down or when you want to go further afield and a buggy isn’t possible. We got one off Vinted for about £20. I like it because I can back carry with our sling but it’s harder to do it without someone helping and I wanted something I could use on my own and feel confident using if she was tired or having a meltdown etc!! (We use a Tula explore if using an actual sling) x
My ring sling goes up to 45lbs and you can hip carry with it. It does take a little trial and error though to get a good fit.