As I have said I have 7 kids and 2 stepchildren and they all have friends who come over and they stay at theirs, I sit and do reading/spellings and homework with them after school, they each do a couple of clubs outside of school, I cook everything from scratch and our house is really clean and tidy. It helps that we are both at home, we run a business from home but it’s around family life, not the other way round.
One on one time, proper one on one time like days out together is not as often as if there were two kids ( for example my oldest daughter does acting and our thing is to go to London a couple of times a year to watch a show, go for a nice dinner and stay somewhere fancy
) but it happens, and daily there are snippets here and there where one of them will come and help me with the cooking or we’ll have a chat here and there, you make the time, even if it’s ten minutes.
I know it’s not the same league as this family and I think I would struggle to keep the standards I do with 3 times the amount of kids ( I know the older 3 are adults but surely you still have a relationship with your adult kids even if you’re not running around after them) BUT I was an only child and my mum didn’t give me hardly any attention, she used to just tell me to go and play or watch tv! So I think if you are the type of parent who wants to spend time with your kids then you will find the time, if not, then it makes no difference how many you have!