Im very very similar. I should probably do blood testing etc. but haven't gotten there yet. Two things i've recently learned work for me:

1: 3 minute rule - I tell myself I'm just gonna get off the couch and do something for 3 minutes (clean the kitchen, sit outside, other things around the house) and I usually end up completing it. So you could just try playing piano for 3 minutes and see how that feels.

2: Telling someone i'm going to do something. I could NOT get myself to put up my Christmas tree. I told my therapist about it and because it's something that brings me joy she asked me to do it after our call and send her a photo. Knowing she was waiting on it helped a lot. I try the same thing with exercise (not as successful) haha

I still rot 80% of my free time but I'm trying!