This isn’t a very good fight especially considering its for two world titles. Artur Beterbiev is 15-0 with 15 knockouts and is seen as one of the most dangerous champions in the sport while Deines recently lost an eliminator and is around European level. Neither has fought recently so ring rust shouldn’t make a difference.
I expect Artur Beterbiev to press forward and use his usual style of heavy handed pressure which breaks his opponents down. I think he will win by knockout within six rounds because hes better technically and has a horrible style for anyone that either can’t hurt him or doesn’t have amazing foot work.