Hi,
Rublev always has been very picky with his rackets, even if those were made of the same spec he always favourited 2 or 3 frames from the set, and he liked to play with those most of the time. He played with H22 for many years, last October/November (2019), he received a set of frames to test, I saw the shipping and I even unpacked some of those myself, there were Speeds, Extremes, Prestiges and Gravity. All blacked out.
It looks that he liked the Gravity(Pro) over the other frames, and they were doing around 20 for him to test different setups (that's the regular process). He picked one (don't know the exact specs, but I can ask those if you're interested), a light one to start so he could add more weight. He also likes the frame to be filled with foam for a more muted feel. He got a set made for him (they we all on the same spec) he just liked 4, and these are the ones that he's been using.
Met him several times and I have to say that he is a very nice guy, very dedicated, his dream is to become number one.