I feel that I have experience in a lot of what you are asking. You only say that you were thinking about it and wanted opinions.
I am 66 so the age you would be when you have a 10 yr old. I spend a lot of time caring for my 10 yr old niece. She can be exhausting. I also babysit her 3 yr old brother. He is with me for 2 hour stretches. He is less mentally exhausting but it is nice when mum comes out of work and I can say “Aunty will see you tomorrow”.
A close relative, early 30s has had ivf. She was 20 years younger than you and was successful but I was shocked to see how extremely tiring it was. Nerves throughout and the injections were so time consuming. The birth was not without issues. Newborns are a nightmare. That is with a partner around. You would almost certainly have a c section. Imagine being woken multiple times, keeping on top of your housework, cooking healthy meals and doing mountains of washing. That is just the start.
I once read a book about Queen Elizabeth the First. Apparently 4 maids were employed just to rock the royal cradle. It sounds excessive until you have to look after a new born who is just learning to adapt to the world.
I have been looking after a relative’s 8 month old since his mum went back to work. (Yes my home has turned into a full time nursery, but I do like children). I have been with him for up to 8 hours at a time. I cannot imagine doing that without a partner to say - can you watch him while I have a shower/a wee/make a cup of tea.
Back to the 10 year old. Getting her to and from after school activities, negotiating screen time, going on family holidays, choosing school shoes. It is all effort. Fun stuff but it saps your energy. The lucky mums are the ones whose kids want to watch bake off with them. You are more likely to have to learn the names of K-pop stars.
Your idea sounds like a hallmark movie but in real life it sounds like a life-impacting nightmare. If you have enough money to pay for several full- time staff for the next twenty five years, I take it all back.