Ravan ws the villian of ramayan but I will tell some traits of him which will lead to come to the conclusion that if he hd followed dharm so thr may be temples for him.
He was a great scholar of the 4 Vedas. It is very clear from ramayan that he was no commoner but a great chanter of Sam Ved.
He defeated devas, humans etc and became trilokpati.
He composed poem shiv tandav strota is quite impressive
Knowledge on ragas and was a prolific Veena player. He is credited for the instrument Ravanhattha.
Wrote a book ravan Samhita on Astrology.
Great knowledge on ayurveda
Once he was playing veena, the string got break but he didn’t wanted to upset his wife Mandodari who was dancing on its tunes, immediately took out a nerve from his thigh and placed it there, and started playing veena
Today for doing by-pass surgery nerve of thigh is used.
Great knowledge on political science
For this reason ram asked lakshman to go to him and seek knowledge from him before his death.