The base of the camera does get pretty hot, so it's definitely dissipating some heat that way. If it's like the A7 ii then the bottom cover unscrews to reveal the metal bottom chassis. Beyond that is the bottom of the IBIS assembly. I don't have any metal fabrication skills, but three thoughts - either a metal plate "radiator" underneath the camera... Or a hole in the bottom and a small fan... Or chemical cool packs... Like you use for sports injuries...