B.H.
I was totally fine with my only child for years and put everything I could into her. It was affordable, I had time for her, lots of love you name it.
I did though go on to have another child. My daughter's are 7 years apart and because of that we've only had to put 1 child in daycare at a time, by the time I had my first daughter out of the baby,toddler,preschool age where all the hard work is she is a breeze I had my second child and was able to appreciate and relive all the fun baby times again. I thought they're age difference would be a huge problem but it's not my daughter loves her baby sister and dotes on her. It's not bad financially like I said I only have 1 in diapers adn if I go back to work mostly just 1 in daycare.
So maybe having 1 child is all you need but you could also think about spacing the kids out too, they don't have to grow up super close and back to back.