It sounds like your current work life is also kind of stressing you out bc of lack of steady income and benefit reasons. Maybe see how things are in first couple months with baby and how you are feeling. Great benefits are nice to have! Could you quit govt job again and easily go back to current job if not working out again? Could you have baby I'm daycare near by?
I would suggest not making any changes until post baby. Figure out what post-baby life really feels like, what compromises you feel are right at that time (money vs. time -- what's that balance look like to you after baby is born)
You can do all sorts of hypothetical second guessing but until post-baby, I don't think you'll have an accurate picture of what that balance will feel like.
I understand your stress though - hang in there, you'll figure it out
if you *have* to apply on maternity leave, i would.. you can interview, etc, and decline the job if it really isn't the right fit..just stall as long as you can so that you can get a better idea what life is like with baby.
I'd totally try to get your job back after maternity leave. you've been wanting something like this for a long time, and in the long run, i think you'll be happy that you made this decision, so you can be less stressed.