Have 3, 2 are at secondary and y10 and y12.
I was around, and tended to get sucked into DT and art homework in the early years (y7 and 8), but never anything else. They are very able, and at very structured grammars, so same as some other posts - I said I will help if you ask, but if you forget something you will have to take the consequences.
They have been fine: once they got to about y9 neither DH or I could help with maths or sciences. Can vaguely help by playing Devil’s advocate with English or the humanities, but that it is it now!
I feel bad for y4 child: am now working F/T on my NQT year at a primary and broken. I am one of ‘those’ parents my colleagues mutter about and say ‘the mum hasn’t signed their book record for 4 weeks’’ 😁.
I worry sometimes it seems like benign neglect, but they are very conscientious, and at very intense grammar schools, so I don’t want to put any more pressure on them. Our mantra is ‘all you can do is your best, and you know if you have done your best’.
It’s hard OP - you just have to do what works for your family unit x