Trying to use the /data command to edit an Item Frame's rotation doesn't work. It resets the Rotation tag to its default no matter what you do.

Using these commands, you can see it snap back into place when you try to modify the NBT

/execute as @e[type=minecraft:item_frame] at @s run tp @s ~ ~ ~ ~30 ~20
/execute as @e[type=minecraft:item_frame] run data merge entity @s {Rotation:[60f,60f]}

It also seems to reset its rotation no matter what NBT gets modified. Whenever its NBT data is updated it resets its rotation.