The OP is just a kid. I rode a lot in my teens, but then only did career until I picked riding up again at 50 and started really training. I can tell you from experience that at your age, or at any age over yours, taking it easy over the winter is an utter disaster. It'll take a full year's training to fix that mistake. What you need to do now is base, lots of base. Like others have said, ride your effing bike. I don't think that taking all the monitors off the bike is a good idea, not a good idea at all. You want to use those monitors to restrict your activity level. Keep the effort down! Some people really have to work at that. As it is said, most riders go neither easy enough nor hard enough. Build mileage. Mileage is strength. Don't do any intervals. It's OK to ride hills, but don't work at them. Really embarrass yourself, gear down and spin up them. On your trainer, use erg mode. You know about what your FTP is, so set it to 75%-80% and pedal for an hour or so, concentrating on beautiful pedaling. Ride 6 days/week, pretty easy to do now with the shutdown. If you feel tired, just do Z1 on your trainer for 30'. If you're doing it right, shouldn't need an easy day more than once a week.
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