I was in a similar situation when my youngest went to school (I had worked between DCs 1&2, but then became a SAHM so not out of work for so long). DH earned enough for us to have a very comfortable standard of living.
For DC2's first year in school, I did volunteering, partly at the school and partly at a charity shop. This gave me flexiblity for that first year of DC2 catching every bug going, and put something to talk about on my CV. (If you are volunteering, it's easier to cover school holidays and sick kids!)
Then went back to work part time in another school. My volunteering in my DCs school did help me get that. So it's admin, but term time only (slightly different holidays but not significantly so).
After childcare costs, I bring very little into the family pot each month compared to being a SAHM, but I have my own pension again, and feel like it's at least getting me back into work so that when the DCs are older, or if something happened to DH, I wouldn't be trying to start looking for a well paying job having done nothing CV worthy for a decade.
What you can say OP, is you are afforded an opportunity very few adults get, you are able to start again without a requirement to earn a certain level to support a standard of living. You can do a few years of study or volunteering or low paid jobs that might lead towards something you are more interested in doing.
So many people are stuck on a career path they picked when they were little more than kids and didn't have much life experience, and didn't really know themselves. But once they've got to a certain level, and have a mortgage to pay and responsibilities, the idea of starting again isn't really an option. For you OP, it's an option. Embrace it!