Advice on cutting sideways in wood with Dremel T-slot cutter

The Router Bits - Using Slot Cutter Bits wood slot cutter I already and straight bits for dado's in plywood but I'm having no luck at finding a slot cutter Any hints or tips on this? Thanks & Happy Wood Chips, woodland lottery slot cutting needs PREMIUM

wood slot cutter Shank CMT's Slot Cutters are great for splines, biscuits, T–molding & more For biscuit joining use the 532” cutter Available