Please don’t pay attention to the judgemental replies that seem to know everything about your parenting abilities based on one emotional outpouring. And certainly don’t listen to those who think a man is necessary to raise a child.
Parenting is hard. Really hard, yet we’re rarely shown other parents' failings.
It isn’t selfish to recognise that your personal life has suffered. It doesn’t mean you regret or don’t love your children.
I’m sorry I can’t offer any advice guaranteed to solve your problems, but I will say try to put much less pressure on yourself. Perfect parenting isn’t a real thing, and the more things you aim to get perfect, the more you can fail.
My 6yr old has always been good in school but refused point blank to do any work during the lockdown. It was incredibly stressful, with all the screams and fighting, until we decided she wasn’t benefiting from the situation. Less pressure on her, and us, was far better all round.
This might not help, but at least know you’re not alone feeling this way, and you can get through it.