So for some reason I thought Budgie was a cool flavor to go with but I didn't like the DE and switched to Gnome within a few days. There's really no point of having the flavor now and I wanna change it to Bionic Beaver 18.04. Is this possible without losing all of my packages which I assume happens if I install Bionic Beaver 18.04 from scratch. Would appreciate any help on this.
Bionic Beaver relates to Ubuntu 18.04 LTS, being a codename for the release and applies if you're using the Budgie desktop, GNOME or any other desktop. All updates are stored in a 'bionic' directory on
archive.ubuntu.com (or country/local mirrors)
You could just
sudo apt install ubuntu-desktop
and add the default GNOME desktop to your existing machine. At login you can select which you want to use for that session.
Having multiple DEsktops uses more disk space (as you'll have both), you'll have larger updates (both will upgrade), it can also complicate menus, as you'll have more programs installed (that can do the same thing unless both desktops use the same programs), but I like this and have it on my own systems.
If you install using 'something else' & ensure you don't format your partitions (ie. select the same partitions, just overwriting them), the installer takes note of your installed programs, wipes system directories & installs your new Ubuntu into those system directories, then restores the programs you had installed before (or added by you if from Ubuntu sources). It doesn't touch your settings or files either (but this doesn't mean you shouldn't backup - do it always in case of power outage, or accidently formatting your partitions)