I bought the regular S10, but for me it was a choice between the S10 and the S10e. I chose the S10 because of the telephoto lens and also because, once I held it in the hand, I realized that I could in fact wield a 6.1" device!
When it came to the S10+, I didn't consider it because it was too big of a phone for me. Coming from a Google Pixel 2 (5"), I really didn't think I could handle a phone of that size.
As far as overheating goes, my S10 has been pretty cool (figuratively and literally) to use. It gets a little bit warm if I use it while it's charging, but that is kind of my own issue as I know using it while it's charging is not a good idea.
With regards to the cameras between the S10 and the S10+, I didn't need the extra selfie camera on the S10+, as I'm mostly taking pictures of my cat and not of myself.
Please let us know which one you decide to get! They're both really good devices to use!