Russia is always happy about any single opportunity where they can increase the polarization of the audiences. Obviously, this conflict is one of the most polarizing topics, so they will be using it to do their work. The aim with which they are doing it is probably to spread more of the anti-western, anti-American sentiment, with the U.S. still being the chief target of their disinformation campaigns, and probably with the logic that Israel is perceived as the biggest ally of the U.S.
I think the motivation is this primitive. In order to denigrate the U.S., they will be spreading a lot of anti-Israeli sentiments.