When I started lifting, I was in my early 20s, when I had similar goals as you and a tremendous amount of free time.
By the time I hit my “target”, life started getting busy and my free time was replaced by various obligations.
For me, the desire to continue lifting shifted from a goal body to having an hour a day that was 100% mine. Maybe that could work for you as well.
The ever-present fear of losing all your progress also helps.
In maintaining weight loss, the most important validation metric shifts from the scale to the calendar. Getting beyond that first year seems key, and my next goal was to pass 2, 3, and 5 years.
With each passing year, things come up that teach us things. But we're also giving our bodies good time so that homeostasis helps us instead of dragging is back to our old weight. As we will always live in an obeseogenic environment, this will take effort along with homeostasis to maintain.
and also packed on a lot of muscle
As long as you can articulate why to maintain that, then no problem. The bigger point is to have and enjoy the good life and a healthy and fit body is our platform for doing just that now and in the future. It also can be our hobby and that PART we can lose passion for over time. We still need to do some of this stuff for good health. Maintain is a verb, verbs are action words. We can't stop it entirely and expect our health to stay good if we are neglecting it entirely.
Scale back if you decide to, but not to zero. You'll lose some muscle but not muscle that you actually use.
You can look into some performance goals. Do you want to train for a marathon or Ironman? Do you want to compete in powerlifting? Or maybe take up a team sport? These can all give you goals and targets to keep you moving.
I scaled back and tried to figure out what the minimum effective dose to maintain the physique I wanted was.
Results were decent.
Set goals which aren't body-based. Add 20kg to your bench. Try and do a pistol squat. Run a 10k. Enter a competition of some variety.
I think these are healthier goals anyway.
My goal physique changes, unfortunately.