I agree with this approach.
I do actually enjoy children (though childfree) but in terms of time investment, other people's children aren't really that interesting
Family child centred events taking up precious weekends and holiday periods and involving a lot of travel and "cognitive load" are something I've detached from.
As a polite middle aged spinster, I'm mindful of being typecast as the "low status" reliable person who is there to help everyone but doesn't deserve respect.
It's down to me to create the life and environment I want.
Of course I'm available in case of emergencies, or would help out if something specific, but am a LOT happier now I'm either chilling out solo at home or building other interests and social networks and community.
I now am fully booked out with cool stuff and have had some great experiences, grown as a person.
This does take time, so practically it's better to start sooner.
There's no reason to burn bridges or have massive discussions, just detach politely and peacefully. Life is short. You're not rejecting anyone.
As pps say find some sort of compromise - maybe you want to just drop in for a coffee, or reduce frequency, or just for certain occasions. There's no medals for making yourself miserable.
Many men do this with no guilt (you could always make up a white lie to get time back for yourself. Say you've met a man or got some weird health issues or something).