On plywood I always use a compression bit. Up spiral on the bottom, down spiral on the top. Gives a super clean cut top and bottom. Make sure the bit is SHARP.
Don't attempt to resharpen a compression bit as the resharpened bit has less then half a factory sharp bit and resharpening is not cheap to have done.
Another thing about a compression bit is you have to plunge it into the plywood before you start moving the spindle/router so the up spiral on the bottom of the bit is below the veneer on top of the plywood. Otherwise, if you do a standard ramp, the first part of the ramp will have a lot of split and chewed up veneer because the lower up spiral is not down shearing the veneer. It is up shearing the veneer tearing it up and making a mess. Don't ask how I know this..![]()