Format the text in a rollup field (Concatenate?)

Is there a way to format the items in the rollup field to look like this (including brackets on either side):

[“Choice1”,“Choice2”,“Choice3”,“Choice4”,“Choice5”]

I have this formula but it does not work in a rollup field:

'["' & 
SUBSTITUTE(
  Choices,
  ', ',
  '","'
) & 
'"]'

Then I found this sample code:

IF(
  ARRAYJOIN(values),
  "- " & ARRAYJOIN(values, "\n- ")
)

But I can’t figure out how to combine them without an error.

IF(
  ARRAYUNIQUE(values),
  '["' & ARRAYUNIQUE(values,   ', ',
  '",") & 
'"]'
)

All these “,”"’’ are making me go cross eyed. Please help me! :rofl: