MariaDB 10.5

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CREATE TABLE tab( jsdata1 JSON, jsdata2 JSON );
INSERT INTO tab VALUES
('["a", "b", "c"]','["apple", "banana", "coconut"]');

SELECT JSON_OBJECTAGG(Js1,Js2)
  FROM
  (
   SELECT JSON_UNQUOTE(JSON_EXTRACT(jsdata1,CONCAT('$[',@rn+1,']'))) AS Js1, 
          JSON_UNQUOTE(JSON_EXTRACT(jsdata2,CONCAT('$[',@rn+1,']'))) AS Js2, 
          @rn := @rn + 1 AS rn
     FROM tab AS t1
     JOIN (SELECT @rn:=-1) AS r
     JOIN information_schema.tables AS t2
 -- WHERE @rn < JSON_LENGTH(jsdata1) - 1 #redundant for MariaDB, but needed for MySQL
   ) AS j


JSON_OBJECTAGG(Js1,Js2)


{"a":"apple", "b":"banana", "c":"coconut"}