Access Applications directory with Terminal in Recovery Mode

I hope someone can help.

I'm trying to access my Appplications directory in Recovery Mode of my iMac with Terminal. I want to copy a folder to an external hard drive. After updating to Big Sur, my iMac won't start and so I need some files to save. The path I want to access is /Applications/MAMP/htdocs.

When I type ls /Applications/MAMP: it says that there is no such file or directory. When I type ls /Applications: Safari.app and Utilities appear.

When I type ls /Volumes/Macintosh\ HD/users/"username"/Applications .localized appears.

Is there another command I have to use? Is it even possible to get into the application folder?

By the way: I already copied the whole Library folder... maybe it's possible to override the MAMP-files? Or do I need another backup of the htdocs-folder?

Edit: This is the result of diskutil list internal

When in macOS Recovery from macOS Big Sur, in Terminal, the location of the MAMP installed htdocs folder is, e.g.,:

/Volumes/Macintosh HD - Data/Applications/MAMP/htdocs

You can also use the find command to locate it, e.g.,:

find /Volumes -type d -name 'htdocs' 2>/dev/null

The output of that find command would be, e.g.,:

/Volumes/Macintosh HD - Data/Applications/MAMP/htdocs
/Volumes/Macintosh HD/Applications/MAMP/htdocs

The one with Macintosh HD - Data is the one you want.

When in macOS Recovery, using Terminal can be a bit difficult. I find using Disk Utility to backup select folders, saving the DMG Image to an external drive, is much easier, albeit even if copying a bit more than needed.

Disk Utility > File > New Image > Image from Folder…

^{Note that there is no external drive attached and the picture is just to show ease of access to the file system compared to using Terminal.}