There might be lots of programs that do that but nice is it if the data is encrypted in a standard way that also allow other programs and operating systems to decrypt it.

A standard method is using encfs. It is actually not an encrypted filesystem, since each file and directory can be seen. However the directory and file names and obviously the data inside the file is encrypted. This allows easily to copy the data from the phone to a computer as for backup reasons and then decrypt it and work on the data on the pc.

Install on the android phone apps as:

On the linux pc install encfs and a gui front-end as gencfs https://www.linurs.org/gencfs.html.

gencfs allows to do the necessary setup using its gui. For manually doing it at the command line do:

mkdir ~/Phone/Encfs/.crypt to create the directory where the encrypted stuff is

mkdir ~/Phone/Encfs/crypt the directory that serves ans mounting point

encfs ~/Phone/Encfs/.crypt ~/Phone/Encfs/crypt to create the password the encryption method

When done fusermount -u ~/Urs/Phone/decfs unmounts it.

Now copy/synchronize the directories to the phone and start encdroid and import the volume.