Remember “enamel paint”, is NOT enamel. Enamel is GLASS. Porcelain is Ceramic. People exchange porcelain and enamel with fairly reckless abandon.
Porcelain being ceramic is capable of tremendous temperatures, as is Enamel. The top on your grandmothers stove (if it wasn’t bare cast iron) was enamel, which fires in excess,of 12-1500 degrees depending on color.
I had an “eye opening” memory jog when I started my first “rehabbing” project. I spent twenty years in art material and paint sales, as soon as I had a first hand conversation with a very highly regarded restorer, I started thinking about finishes involved and why Grill companies use the materials they do.
Outgassing of paint (brake caliper, or whatever) volatile vehicles such as any number of toluene, benzines, methyl ethyl ketones are extremely toxic especially, under the kinds of temperatures achievable in a grill.
To cut to the chase,
Simply DO NOT PAINT interiors, ever! Period!
If you have access to a large enough kiln, enamel coating material, proper safety equipment, appropriate surface conditioning equipment, reglazing might not be too tough. The hard part is equipment accumulation, and waste disposal.
That’s all based on experience gleaned from an appreciation of glass and, enameling art.