I once entered in a class and heard the familiar Windows 95 startup sound. Thinking it was a VM, I went and checked: a group of students were customizing their Linux distribution to look like Win95.

I asked them if they knew fvwm95, the window manager of my youth; they didn't, and I suddenly realized that a) it's not supported anymore b) they were all born after Windows 95 was released c) I'm slowly getting old.

The wm in twm and fvwm stands for window manager. A desktop environment contains a window manager, though its much more than merely that. Just like an apple is a fruit, but not every fruit is an apple. Comparing a DE with a WM is apples to oranges. You can probably look up the exact differences in Wikipedia.

One can try out Xfce on a Raspberry Pi as its the default DE on Raspbian (full default install). It is blazing fast. Since most people are accustomed to Windows 7 and Windows 10 (or Server equivalents) it works reasonably easy for them. You can't say the same for the two (or any) WMs you mention.

My default "WM" is a TUI called Tmux. I use it on every practically every computer I use.