I was trying out different materials on yoyos to see which one does the most damage but has the most durability and speed when I noticed somethings, speed carries over between yoyos when switching to your off-hand. I had two yoyos, a cobalt one with a manyullyn axle and string cord and a manyullyn one with a manyullyn axle and string cord, so it could be a fair test. I had the manyullyn one in my off-hand and the cobalt one in my main hand. I threw out the cobalt one and switched to the manyullyn one. Surprisingly it moved at the same speed as the cobalt one, which enabled me to absolutely destroy everything. I tried to show it in a photo, but I couldn't ¯_(ツ)_/¯

The damage doesn't carry over, it stays independent of the yoyos