Not only not harmful, but darn near perfect. Way to go. Sounds like a sensible regimen. You'll gradually get stronger and be able to do more on the group ride, not harder, just more. Just got back from a 40 mile group ride, 3 hrs. 2000'-2500' depending on which Garmin one looks at. Another Perfect Ride™. I'll gradually increase the ride length over the summer, up to maybe 75 miles, same amount of climbing per mile. The moderate mid-week rides are very important. This was our first group ride since Covid started. I haven't uploaded the ride yet.

Edit. I uploaded to Strava. I have a premium account, which gave a Relative Effort score of 237, "Massive". I had over an hour in HR Z4, 13' in Z5. I was on the tandem with my wife. I was trashed at the finish, but didn't cramp. TrainingPeaks gave a hrTSS of 218. We were chasing a couple guys our age on electric assist bikes.