There are companies that sell pocket door slide kits for cabinets. The slides are for how deep the cabinet is. If you have them built inside the cabinet, you can't have shelves in there since the doors pocket into the area. Otherwise you would have to have custom slots built into the outsides of the cabinets to pocket the doors if you want shelves inside the cabinets.

https://www.semihandmade.com/

check Semi Handmade cabinets. They make special items for IKEA cabinets.

Ikea is fundamentally incompatible with pocket doors. The sizes they offer are too limited. The pocket itself takes up space, and would need to be larger than needed, wasting space, due to the width limitations of Ikea cabinets. https://www.hafele.com/us/en/product/pocket-door-system-accuride-1332-with-35-mm-hinge-kit-/P-00875694/

Pick a more full featured cabinet line. That is an expensive ask in any cabinet line. It also gets left open most of the time, and just ends up breaking after a while.

I have room to install the hinges outside the cabinet, but then the standard door will have a bit of an opening in the middle because now the cabinet doors hing on the panel outside instead of the cabinet box.

or

I can use hinges inside the cabinet which means I would need smaller doors that go inside the box instead of sitting on top of it.

Seems like either way I need custom doors. right?

And custom boxes. Pocket doors need a pocket.

I haven't done it yet, but.....Ikea doors go in FRONT of the cabinets (when closed), but pocket doors have to sit INSIDE the cabinets (when closed). So to make it work you'd need to buy a wider cabinet (than the two doors) and hack it down to be a little wider than the two doors. Any shelving needs to be a separate tower inside where the stored doors reside.