Postgres 10

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.

CREATE TABLE user_boards( ID INT, boards jsonb )
INSERT INTO user_boards 
VALUES(1,
       '[{"id": "7beacefa-9ac8-4fc6-9ee6-8ff6ab1a097f"}, 
         {"id": "1bc91c1c-b023-4338-bc68-026d86b0a140"}]'::jsonb)
1 rows affected

UPDATE user_boards
   SET boards = (SELECT jsonb_agg(j.elm)
                   FROM user_boards u
                  CROSS JOIN jsonb_array_elements(boards) j(elm)
                  WHERE j.elm->>'id' != '7beacefa-9ac8-4fc6-9ee6-8ff6ab1a097f'
                    AND u.ID = user_boards.ID
                  GROUP BY ID)
   
1 rows affected

SELECT *
  FROM user_boards
  


id
boards


1
[{"id": "1bc91c1c-b023-4338-bc68-026d86b0a140"}]