I mean, a lot of it is known about, or reasonably ought to be, before having children - Ok you can’t know exactly what something is like until you experience it but you know they will place a restriction on your life, will cost a lot of money, impact your career/earning, etc.
My 2 are grown up now or almost and whilst I don’t regret becoming a mother I really really didn’t enjoy having young children. I just wasn’t massively cut out for it. I struggled with patience and the relentlessness of it. I thought I’d be better at it than I was but then given my own mother wasn’t massively cut out for it when we were young either, it shouldn’t have really been a surprise. I have a much better relationship with my own mum now as an adult than I did as a child.
What I find hard even now is the constant worry about them, I think that’s just hardwired in. In some ways it’s even worse when they are adults and you can’t control what they do. This thread has been helpful actually as I saw a mention of therapy which I had never even thought about but which may help.
How I would put it is not that I regret having them but that I think I’d have been just as happy if I hadn’t. I got pregnant easily twice and so whilst I wanted children I never had a longing for them if that makes sense.