It's strange that we go from Rhodian slingers of antiquity to not seeing any at all in the medieval era.
hi! there's room for more input here, but meanwhile you may be interested in a few earlier posts
Did military use of the sling die out in the middle ages? If so why? - featuring /u/Ambarenya
Why did the sling fall out of favor as a weapon of war? - /u/Theamazinghanna
related posts that may be of tangential interest