KDE uses less RAM, you can fact check quite easily.
Depending on the distro it ships with more or less stuff, but a few games, an office suite, media players for audio/video and in some cases a partition manager, are all necessary tools in any setup, at least in my book.
I don’t see the bloat.
I love Firefox and it’s my main browser on laptop and mobile.
But as a KDE user, seriously, fuck it. It’s a mess.