Merging volumes to install an operating system will be highly complicated and make the system more vulnerable. Your current setup is fine. Storing data on another disk is not at all a workaround. It is a perfectly viable solution to expand space for data storage.
You can very efficiently and easily organize data storage in Linux using symbolic links. Thus, you can easily and seamlessly access any data from within your home directory, even if it is stored on another partition.
Suppose you have a "Music" folder taking a lot of the 50GB. Move that folder to the /mnt directory on the other drive. Now create a symbolic link "Music" in your home directory that points to the real Music directory under mnt: now you can access your Music from within your home directory just like before.
To create a symbolic link:
Method 1: using Files
- Open two windows of Files, one open where your moved "Music" folder is, and one open in your home directory, where you want to create the link.
- Hold Shift+Alt. Drag the Music folder to the other pane and release the mouse button: a symbolic link "Music" will be created that, for all daily uses, acts and feels like a real directory.
Method 2: terminal
Use the ln -s command to create symbolic links, e.g the command to create a symbolic link "Music" in your home directory that refers to the real folder "Music" on the mounted disk.
ln -s /mnt/Music ~/Music
