It is a complex question. I think that you first have to analyse how you use the space you have. Do you use it all, or are 3 of the bedrooms never used, except when the family call. Are they all used, even then. The same with the downstairs, as someone said, is it future proof.
What about the garden, how big is it? Can you cope with t, can you afford a gardener itf it becomes too much for you.
The house needs all the work you state because presumably you just haven't done anything in the past, even though you can see that all this work was been building up. The question arises about how motivaated you would be to do all the things you think need doing. You are clearly not natural house nurturers, how would you cope with all the months of mess and chaos thata all this work would entail.
Where do your children live? Is it easy for them to visit you and vice versa? Is there suitable property that you could downsize to in your area or will you need to move elsewhere.
As I said you are faced with complex problem that runs to more than just getting the house in good order.