Nevertheless there's a lack of variety (3,3,4)
I believe the answer is:
all the same
'nevertheless' is the definition.
(synonyms)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for all the same that I've seen before include "everyone is in uniform" , "Nevertheless - identical" , "anyway" , "In any event" , "still > unimportant" .)