Export the texts to a different file for each song?

[ohrenkino]

Did you find the action to export the cover? You would need to park it in the folder before you can import it to another file.

Now,
to get the data from the text file into a tag field, you can use the function Convert>Tag-file - Tag".
You have to tell MP3tag where to put which piece of data.
As you exported the data with

@ohrenkino

%_filename_ext%/%track%/%title%/$replace(%unsyncedlyrics%,$char(13)$char(10),#)

which led to a line in the text (e.g.)
5 - obladi.mp3/5/Obladi Oblada/Obladi Oblada#life goes one
you now have to define a pattern for the function "Convert>Text-File - Tag" to tell MP3tag which part of the long string is meant for which field.
So use the same list of fields that you used for the export:

Pattern: %_filename_ext%/%track%/%title%/%unsyncedlyrics%
this should select the line where the data matches the filename and then put
5 into TRACK
Obladi Oblada into TITLE
Obladi Oblada#life goes one into UNSYNCEDLYRICS

As you probably do not want the "#" but see the line breaks again, replace the # with the 2 control characters 13 and 10 which represent the line break:

@ohrenkino

action of the type "Format value" for UNSYNCEDLYRICS
Format string: $replace(%unsyncedlyrics%,#,$char(13)$char(10))

The last action to import a cover should be easy to test; I don't repeat it here.