I had two Caesarians, 16 months apart. No Covid, but like you, no help after either of them. Our first daughter was, and still is, a very active person, and I did occasionally find it hard to keep up with her while healing and caring for a newborn.
I agree with Nicole that it’d be a very good idea to talk it through with the Consultant: tell them about lack of help; previous slow healing experience; your concerns about caring for a toddler and a baby while healing and not wanting to pick up a larger child. If you want to throw an extra in, I found that it was hard to keep little hands and feet, and a bouncy bottom away from the incision area. All was well in the end.
Will there be anyone at home with you for the first weeks after after the birth?