Couple days a week is a great plan. My former, now retired, coworker watches her grand babies one or two days a week. She loves it. Anything more than few days would be too much. It’s exciting.
We babysit our 7 year old granddaughter (she is my step but we don’t call it that) every other weekend. My stepdaughter is single mom and has extra job on the weekends. It’s fun. My grandson lives way too far to babysit regularly. I do when I travel to them.
But otherwise if that doesn’t work, part time job is a good idea too. Sitting home together is great here and there. All day every day might not be best.
Hope you come with something. Can’t wait to hear when the baby is born. Is it a boy?