Regardless of Murata is active or not within the past 2 years, I already pointed out his experience is lacking compared to GGG. Murata's total fight was 16 against Canelo's 43 with almost a clean record, the gap was too wide. Murata just also consider to bout with GGG because he filled the vacant slot that was left by Canelo as we know the latter is moving up a weight class. Again as I previously mentioned, Murata got the full WBA Super Middleweight champion not by fighting for it. The fight against GGG is his first fight since attaining that title.
Right, and the level of opposition of GGG as compare to Murata is very diferent. GGG has far fight superior level of boxers, while I would say that Murata only B-level fighters. And add that to his ring rust and inactivity for 2 years and we will see that GGG has all the advantage. The only thing that has on Murata is that he is fighting on a familiar territory, because this fight will be in Japan.