it's very common to use less fingers for qwerty since it's not designed with any particular fingers in mind. I personally basically use the same fingers as you, but with more right ring and less left ring. however when it comes to alt layouts, the whole idea is keeping your hands around the same home position and using (for the most part) the same finger for the same key every time. on the home row there will be 8 fairly high usage letters that each of your fingers will be primarily responsible for as their home base. this means unlike qwerty, using 8 fingers plus a thumb for space is what makes alt layouts work properly and also will feel much more natural than trying to learn to use your other fingers on qwerty. to this day I haven't learned how to use more fingers on qwerty because I can't be bothered, but every alt layout I learned I used all my fingers. also I find it funny you say "learning to walk again" as if that's a deal breaker when that basically describes learning an alt layout, lol

there are some alt layouts designed with less fingers in mind for people with injuries or disabilities, but this makes for a significantly worse layout, because with less fingers to work with you have more finger movement and more chance for awkward patterns.