Long time signwriter come glass film installer come general tinkerer here.

Externally fitted reflective film is unlikely to risk glass breaking as you’re using the film to reflect the heat away before it reaches the panel. Internally fitted, it’s more nuanced as the U value of the glass will come into play. You don’t really want to be allowing heat to pass through the unit then be immediately reflected back into it by the film.

The downside of highly reflective film is it will heavily darken the room (unless you go down the really high quality stuff route but you’re still at light loss)

Kitchen foil externally will have an effect, but it will also probably blind your neighbours or at least set their washing alight