I don't know if you've already tried it, but your laptop seems pretty capable (relatively), and should run Plasma or Gnome fine.
List of distros I think you should try out (in order): - Linux Mint Debian Edition (I like Cinnamon) - Linux Mint (If there are any extreme errors with normal Linux Mint, will look and mostly function the same) - Fedora (not based on debian) - EndeavourOS (this neither)
Tutorial before I realized that switching DE/WM is not supported in Linux Lite, but you can still try since you're probably going to reinstall anyway.
To install Plasma, open a terminal, and update the package databases, and upgrade the system.
sudo apt update
sudo apt upgrade
Plasma along with KDE's applications' package name is kde-full, and is likely what you want to install.
I'm not completely sure, but you may be asked to select a display manager, select sddm (?).
Install the DE you want using its packages name.
sudo apt install __
After the installation is finished, reboot, and you should be greeted by SDDM, looking way different from before. If it doesn't change, then idk.
There should be a menu in the top left corner, click on it and change it to Plasma or whatever.