What I’ve used for this purpose is one of these. And I can attest that 60C° is nowhere near high enough to set that kind of thing for purposes of getting a Google Pixel 3a off safely.
But I bet ThetaDev is right that a flat plate heater can work just as well when set to lower temperatures because they heat the whole screen at one time.
You are thinking about a soldering plate? Those go up to 300°C or some times 400°C.
A phone screen is fixed with hot glue, that starts to melt around 60°C.
What I’ve used for this purpose is one of these. And I can attest that 60C° is nowhere near high enough to set that kind of thing for purposes of getting a Google Pixel 3a off safely.
But I bet ThetaDev is right that a flat plate heater can work just as well when set to lower temperatures because they heat the whole screen at one time.