Unknown Virtual Drives and Volumes

The additional volumes you see in your Etrecheck report are parts of macOS that are normally hidden from view. There is nothing to worry about there. (EFI, Preboot, Recovery, VM, Update) This is a normal installation. Also, not to worry about hidden files & folders as aliases, there are lots of hidden connections (aliases & links) between various parts of macOS - don't go fooling around with them, you could corrupt your system.

There is nothing in your Etrecheck report that would give me any concerns. It's about as clean as it could be.

To add to the very well explained information from @MartinR above

This link below will provide additional information specific to the drive structure in macOS 12 Monterey.

Depending on if the machine is Intel Based or Apple Silicon Based machine, the structure is a bit different.

Boot disk layout in macOS Monterey

From what I see, the only area that could be improved upon would be to Purchase an External Drive that is 2 1/2 x to 3x larger than your Internal Drive Drive Capacity ( 512 GB x 2 1/2 to 3 x Larger External Drive )

Then use Time Machine Backup to protect your important Personal Information

You are seeing files & folders that are normally hidden from view in macOS. Whether you intentionally turned on their visibility or not, I recommend that you turn it off. They are areas of the operating system you should not try to do anything with yourself, especially if you are not conversant with the innards of macOS.

I am going to defer to @MartinR as he was the first on the scene to this question.

Besides, too much info from more than one Contributor at the same, can get confusing to the Author( you ) of this question.