To use a different example, let’s say you were going to the gym 3-5 hours a week and decided to start working out at home. You do the same or less hours of workout and have no idea if your workouts and lifts are getting progressively harder or not, but you do a max lift and the weights are the same or lower than before you started. The obvious answer would be to track your training and do more reps or heavier weights. No pain, no gain. It’s no different with cycling.
I think you can turn this around pretty quickly by monitoring your workout time and progression levels in the zones that will impact your next FTP test. I wouldn’t expect massive gains from month to month, those tend to come early in your career, but I would expect steady progression (or if you’re aging, the ability to maintain). Good luck!