Hi Frank, I weigh the same as you, 74-75 kg, have however been winging since 2019 so I used to have the 85 and 75 in my quiver, in the meantime I spend most/almost all my time on the 4'9"/65L, as I like to jump and the smaller board makes a big difference in rotations. However for flat water/light winds where I live in Munich/Garda, I will often take the 4'11" Sky Style/75L as it is so much more comfortable for starts/if the wind drops.
So I would really recommend you to go down one size to a 75L, the 4'11" is a bit more compact than the 5'2" you have and should be no problem in terms of flotation, the smaller boards are actually easier to pump as you sink the board slightly when doing the pump movement, vs a higher volume board which sticks to the surface.