Struggling with Plumeria — would appreciate advice

I want to be honest: I'm not getting great results with Plumeria and I'm not entirely sure why. spider mite infestations in hot dry conditions has been a recurring problem despite my attempts to address it. I've been focusing on maintaining temperatures above 15°C throughout the year based on everything I've read.

fast growth in warm humid conditions is there in glimpses, which tells me the plant has potential in my conditions. I have it in a warm humid conservatory or heated greenhouse which might not be ideal. active growth flush when moved outdoors in early summer showed some improvement. Two stars for now — not the plant's fault, but not a success yet. I'll update if things improve.