INSERT @T (JsonArray)

VALUES ('["I3","I23","B1","B3","B2","B4","B6","I1","I11","I4","I14","I24","I34","I5","I15","I25","I35","I6","I16","I26","I36","I21","B5","I31","I11","I3","I1","I31","I21","I21","I5","I4","I3","I21","I4","I23","B1","I23","I3","B1","B2","B3","I15","I15","B2","I13","I2"]');

SELECT *

FROM @T;

SELECT DistinctArray = JSON_QUERY(CONCAT('[', STRING_AGG(QUOTENAME(oj.Value,'"'), ',') WITHIN GROUP (ORDER BY oj.[Key]), ']'))

FROM @T AS t

CROSS APPLY

( SELECT oj.Value, [Key] = MIN(CONVERT(INT, oj.[Key]))

FROM OPENJSON(t.JsonArray) AS oj

GROUP BY oj.Value

) AS oj

GROUP BY t.JsonArray;