Get roof racks with bars that protrude over the sides like this. (Doesn't matter what brand)

Then, grab yourself a set of tie downs something like this
https://www.surffcs.com.au/shop/surf-auto/fcs-cam-lock-tie-down-straps. Surf ones are nice since they'll have some kind of neoprene around the buckles to protect your board.
This way you can loop the ends of the tie downs over the roof rack bar ends without having to thread the straps over and under the bars each time you're loading. Takes 2min instead of 4min.
Or, you could buy some fancy sup carrier for $500 and do it even quicker with some extra security. I'm a tightarse so took the $20 option.