@silverwizard @artcollisions @SurlyAmy I was about to jokingly suggest that you could drill, tap and use screws/bolts, but then my Google search resulted in ceramic bolts and now I want one. Or a bag of them. They look too nice but even more fragile.
If I had to repair a mug I'd either use the 50 °C resistant epoxy and hand wash it afterwards or (if it'd be the handle) use any temperature resistant glue anyways.
(Photo source: https://www.ortechceramics.com/products/ceramic-screws/ceramic-screws-2/ )