If the risk of physical data theft is high, your data is at risk. If the risk of physical access to you machine is rather low, encryption might actually increases the risk of losing your data simply by the chance of losing the means to access your data (forgotten passphrase, lost hardware key…).
+1 Plasma. However, I don’t dislike gnome. Gnome just doesn’t fit my personal taste of workflow and customizability. Other that that, gnome did a pretty good job on the look and feel department. I feel at home on Plasma (and almost at home on xfce)
I sounds like you have to apply new cooling paste. This might be a pain to do on a laptop but certainly worth it. Another distro probably won’t do the trick, whether it’s minimal or not.