I don’t have a partner and have 50% custody of my child. It’s difficult to do it on my own, but as long as I capture lost time it works. For example, we do math, reading and spelling while we are in the car.
I also use voices (my kid is 8 so it still works). We have two characters - Monkey and Lulu. They are very useful because Monkey is a monkey so was never educated in a human system. He always has lots of questions (and questionable pronouncements).
If any busy parents want to meet Lulu and Monkey, get in touch and we can set something up. I’m a big fan of characters - they are a great way to review school material and it’s amazing hearing my kid explain things she has learned back to me.
(Edit - I should note that I have a large amount of economic privilege. My situation may not apply to everyone.)