I went with GNOME just because I’m used to it and want stability as my main focus but I was wondering if using one DE over another can affect security or privacy at all? Or is that all dependant on the distro you are using?
That question is very broad.
Yes, double the DEs installed will mean double the possibilities for vulnerabilities.
Also, I know no Linux Desktop that is actually secure. Like having a real password manager or not sharing the clipboard.
Privacy? No? But just look at what data they collecty it is harmless.