There are horizontal rotary encoders with click functionality (The component is called EVQWGD001). Unfortunately the pin layout differs from the vertical rotary encoders so you need a custom PCB or hack some custom wiring together. They're more common on split keyboards from what I've found.
You can buy a preassembled split keyboard with this from https://ergomech.store (I've been looking at purchasing one from them). There's also a seller on etsy who offers split keyboards with the horizontal encoder.
You can buy a preassembled split keyboard with this from https://ergomech.store (I've been looking at purchasing one from them). There's also a seller on etsy who offers split keyboards with the horizontal encoder.