ak
I prefer KDE because of its modern look and customizability (it may be the most customizable option out there), though Gnome is also a good choice if you like feature-rich environments. I never really tried others, but I heard good things about Cinnamon. If you prefer a simpler environment without all the flashy stuff, there are options, too.
I recommend taking a look at comparisons. Though most DEs can be themed to look wildly different than their default settings, I believe that the first impression is important. Make a list of possible candidates, research their toolkit (for example KDE makes use of Qt, while Gnome is GTK-based) and what default apps they offer (if you want an environment which doesn't look like Frankenstein did a number on it). There are many lists online comparing the different DEs in various ways, for example
itsfoss.com/best-linux-desktop-environments
lifewire.com/best-linux-desktop-environments-4120…
makeuseof.com/tag/best-linux-desktop-environments
etc.