Foremost - Recovering encrypted PGP & 7z archives

I’m a former Windows power user, now a Linux newbie slowly learning the ropes.

I recently used Foremost to recover data from a USB drive that died; ironically during the process of backing up its contents.
Foremost was able to recover pretty much everything I had in that USB, specifically from a .img disk image I made before discarding the thing.
With the exception of archive files.

From memory, I remember that the USB contained at least 2 encryted archives; one in PGP format and another in 7z format.
With proper configuration of the .conf file, I’ve already been able to make Foremost detect 7z files. However, it outputs hundreds of “chunks” rather than 1 complete archive, far in excess of the size of the actual archive I’m trying to recover.
If it makes any difference, the 7z archive contains only video files, in the 3gp format.

I also recall having non-encrypted 7z archives in the drive, wich Foremost isn’t recovering neither.
My question is: is this inherent to the nature of archive files or encryptation? Or is this a simple matter of my .config file still not being properly written?
I can post the .config file if it helps.

As for the PGP file, I have yet to find a configuration tho successfully detect it. This makes me wonder that maybe the file may actually be a gz.pgp or tar.pgp, using GNUPG if I recall correctly.