Struggling with Pine Bonsai — would appreciate advice

I want to be honest: I'm not getting great results with Pine Bonsai and I'm not entirely sure why. spider mite and scale in stressful growing conditions has been a recurring problem despite my attempts to address it. I've been focusing on wiring branches during the growing season while wood is flexible based on everything I've read.

living art form that reflects decades of patient cultivation is there in glimpses, which tells me the plant has potential in my conditions. I have it in a bright indoor shelf for tropical species only which might not be ideal. repotting temperate species in early spring before buds break showed some improvement. Two stars for now — not the plant's fault, but not a success yet. I'll update if things improve.