Life is giving you a hint here.....Keep your RZ and obviously 1 year of in activity doesn't tell you you will not enjoy the use again.
I have an F6, 2x F100, 2x 601 and a bunch of wonderful glass to go with them. But when I go on vacation, it's the zorki and the FM that goes along for the ride. There is a time and place for everything an maybe that cycle had not come around before you sold the RZ.
I've got a 645 that lights up my eyes everytime I use it. It was 3 years between the last shoot and the time before. I know it will have the same effect the next time I use it.
Keep this RZ and consider yourself nuts if you let it go again!