Duplicate 'Unknown Album' listings for the same artist in Music app
Since you've got access to iTunes on a Mac, the way I would try to achieve what you want is as follows:


Launch iTunes on your Mac
Ensure you have your music library selected
Choose Songs in the lefthand pane
You should now see a list of all your songs
Filter your list by Artist
Now scroll your list so you have the particular artist in view
While holding the command key down click on each of the songs you want to group together - this should highlight them all
Now right-click on one of the highlighted songs and select Get Info (or just use the commandi shortcut)
You'll should get the following prompt:





Click on the Edit Items button
Now start with the Details tab and ensure all fields are blank to begin with and then enter details for Artist, Album and Album Artist) - for album I would replace 'unknown album' with the correct album name (if it exists) or something appropriate like Cryptic's Freddie Gibbs Compilation)
Then select the Artwork tab and if artwork already exists right-click on it and select the Delete Artwork option
Now move onto the Options tab and make sure the media kind is Music (I imagine it already will be)
Finally check the sorting tab to make sure that the metadata you completed at Step 11 is reflected within the fields under the Sorting tab
When you've finished with all the metadata, click on the OK button
Now sync your iTunes library as you normally would to see if the changes are reflected on your iPhone


NOTES:


If the above doesn't work then try again but at Step 11 ensure you select the Compilation option
If you have iCloud Music Library and/or iTunes Match enabled, it's unclear how those services may impact what you're wanting to achieve, so please report back using comments below to let us know how you go.