The simplest explanation for this is the fact that the desktop apps are native apps and not based on the massive and sluggish electron framework.
Unfortunately, there aren't many native applications any more. At this point I'd prefer a Windows application that works in Wine over yet another "cross-platform" Electron webbrowser-with-builtin-website.
No they haven't. The discord electron app is a trash fire. I use discord in Safari. It's just as bad UI and UX and slowness as the electron crap, but at least I get a few more hours of battery life...
Since I removed the electron garbage from my phone, my battery life tripled from one day at most to three days...