Science confirms habit

I use Training Peaks software called WKO. I don’t actually use their online version, but if I were coaching a lot of people it might be a good option. As an addendum to getting their software, I follow their coach knowledge activities online. Just the other day they put up a post about how someone’s latest research conclusively shows that one 3-5 hour ride each week is optimal for almost everyone from novice to serious amateur (pros are different).
If you do sprinting on the track or 24 hour MTB racing (or anything in between), the one long ride per week thing is probably for you.

That ride should be in the “sweet spot” of around 80-90% of FTP. So you can’t just cruise and you can’t hammer yourself either. This is pretty much what I call an Endurance ride in my programs.
If you don’t currently do one of these each week then add it in and it might provide that missing element of fitness you’ve been searching for.