A small plate raised up slightly should help cone-cat eat. You could also try hand feeding him (disposable gloves, for food safety and because cat food is gross).

If possible, try and find a plate and something to place it on that is smaller than the diameter of his cone, so he can get to it. May not even need to raise it, just use a small, flat plate. But raising it up will help if he's cone is large, he might not be able to reach it.

Edit: you could also try something entirely different, such as a sock repurposed to fit his leg, so he can't lick it, but wouldn't need the cone. You could try securing it with a scrunchy. You could also attach the repurposed sock to a body suit (I made one out of the leg of my old leggings), sew the sock onto one of the holes for his leg, and that way no cone, and less likely to come off.

You could also try vet wrap bandages, instead of a sock, it isn't adhesive to fur, just itself, and you could again secure it with a scrunchy.

I keep editing because now I'm going full mcgyver on this haha