Funny. You sound a lot like me. 54. 3 kids. Getting back into riding...
I have gone full throttle into mountain biking. It helps my 18 year old son loves it and I live in the PNW where we have trails everywhere.
First, not sure if this will fit but it is sitting in my basement looking for a new home. It is yours for the shipping. A cool vintage part. PM me and I can put a caliper on it and give you dimensions:
Other solutions are.
1) Larger, low pressure front tire. On my mountain bike, I have ridden a 2.5'' tire well under 20 psi and it rolls pretty well. The resistance is supposedly on the rear tire. I am not suggesting going this low for street riding, but I bet you can go fatter and lower.
2) You may consider a shock fork? Here is a link for many many such forks:
https://www.pinkbike.com/buysell/list/?category=9
You will want to do some research. There are a number of variables that determine fork fit. For your needs, you can buy an older, now not desirable lower travel fork. You are not smashing rock gardens, but absorbing small bumps. Something around 80mm travel should be cheap and take the bumps out.
Note: I would not do all three of these. One solution will probably solve this.