You made it clear you are not interested in hostels, but if I was you I would at least know where a good hostel is near the airport so if you change your mind before you leave EU, you could stay there for a night instead of camping on your last night. You never know if it might be raining, in which case if you had their phone number you might want to call and see if they have an openning if you change your mind at the last minute.
I have never even considered a hot plate on a camping trip, but I sometimes have carried a small immersion heater so I can make a cup of coffee in the morning if I am at a motel. Looks like REI no longer sells the 240 volt one.
https://www.rei.com/product/781694/r...-heater-120240
If you have never used an immersion heater like that, you put the heater in your cup of water before you plug it in. And you unplug it before you take it out of the water. If it is plugged in for even a second and not immersed in water, it will immediately burn out. The heater is in the cup in my photo, next to the powdered instant espresso jar.
I was going to suggest you get one of these before you leave, but since REI no longer sells them you probably could not get one soon enough.
I am not suggesting it as a substitute for a hot plate to cook on, but it can make a cup of boiling water if you have a packet of ramen or something like that. Then you have an alternative to use if you have any delay in getting your hot plate.
Since motel rooms in EU generally lack coffee makers, I always bring my heater to Europe with me.