I own the z690 version of this board and I find what they did on this version really interesting.
The reason I picked the z690 steel legend is I felt the way they drifted away from the way the industry is going was nice for me, it has extra pcie connectivity which is important for me and kept 8 sata ports.
Now this z790 version, has significantly nerfed the pcie connectivity. On the z690 board you have 2 1x pcie slots, and 3 16x slots, the 3 16x slots run in x16, x4, x4 respectively. I use the second 1x slot for my soundcard, and the 3rd pcie x16 slot (x4) for my pcie SSD which requires 4 lanes.
On the z790 board this isnt possible, the x1 slot I use is removed, and the 3rd x16 slot is only x2 lanes, first time I ever seen a x16 slot on a board only give x2 lanes. Change likely forced by intel's changes which removed 8 gen 3 lanes from the chipset.
The z790 version has a nice change where they added 3 extra type A usb ports, the z690 board is mediocre with only 5, however its another give and take, they removed bios flashback from the z790 board which is there and I used it already on the z690 board.
Finally the z690 board has what I think is a design flaw with the placement of the m.2 wifi slot, any modern 2+ slot GPU will cover it up and cause issues with the fragile wifi antennae cables, I had to be really careful slotting in my gpu, they seem to have realised this on the z790 board as they changed the placement of the slot so the end of the card wont be under the GPU. How they didnt discover this before shipping the Z690 board I dont know.