JSON_EXTRACT / JSON_DETAILED is slow for large json documents

SET @j10 = (SELECT CONCAT('[', REPEAT('{"a":1,"b":2},', POW(2, 10) - 1), '{"a":1,"b":2}]'));

SET @j11 = (SELECT CONCAT('[', REPEAT('{"a":1,"b":2},', POW(2, 11) - 1), '{"a":1,"b":2}]'));

SET @j12 = (SELECT CONCAT('[', REPEAT('{"a":1,"b":2},', POW(2, 12) - 1), '{"a":1,"b":2}]'));

SET @j13 = (SELECT CONCAT('[', REPEAT('{"a":1,"b":2},', POW(2, 13) - 1), '{"a":1,"b":2}]'));

SET @j14 = (SELECT CONCAT('[', REPEAT('{"a":1,"b":2},', POW(2, 14) - 1), '{"a":1,"b":2}]'));

SET @j15 = (SELECT CONCAT('[', REPEAT('{"a":1,"b":2},', POW(2, 15) - 1), '{"a":1,"b":2}]'));

SET @j16 = (SELECT CONCAT('[', REPEAT('{"a":1,"b":2},', POW(2, 16) - 1), '{"a":1,"b":2}]'));

SET @j17 = (SELECT CONCAT('[', REPEAT('{"a":1,"b":2},', POW(2, 17) - 1), '{"a":1,"b":2}]'));

SET @j18 = (SELECT CONCAT('[', REPEAT('{"a":1,"b":2},', POW(2, 18) - 1), '{"a":1,"b":2}]'));

SET @j19 = (SELECT CONCAT('[', REPEAT('{"a":1,"b":2},', POW(2, 19) - 1), '{"a":1,"b":2}]'));

SET @j20 = (SELECT CONCAT('[', REPEAT('{"a":1,"b":2},', POW(2, 20) - 1), '{"a":1,"b":2}]'));

SET @t0 = NOW(6);

DO JSON_PRETTY(@j10); SET @t10 = NOW(6);

DO JSON_PRETTY(@j11); SET @t11 = NOW(6);

DO JSON_PRETTY(@j12); SET @t12 = NOW(6);

DO JSON_PRETTY(@j13); SET @t13 = NOW(6);

DO JSON_PRETTY(@j14); SET @t14 = NOW(6);

DO JSON_PRETTY(@j15); SET @t15 = NOW(6);

DO JSON_PRETTY(@j16); SET @t16 = NOW(6);

DO JSON_PRETTY(@j17); SET @t17 = NOW(6);

DO JSON_PRETTY(@j18); SET @t18 = NOW(6);

DO JSON_PRETTY(@j19); SET @t19 = NOW(6);

DO JSON_PRETTY(@j20); SET @t20 = NOW(6);

SELECT

    TIMESTAMPDIFF(MICROSECOND, @t0, @t10) AS `@t10`,

    TIMESTAMPDIFF(MICROSECOND, @t10, @t11) AS `@t11`,

    TIMESTAMPDIFF(MICROSECOND, @t11, @t12) AS `@t12`,

    TIMESTAMPDIFF(MICROSECOND, @t12, @t13) AS `@t13`,

    TIMESTAMPDIFF(MICROSECOND, @t13, @t14) AS `@t14`,

    TIMESTAMPDIFF(MICROSECOND, @t14, @t15) AS `@t15`,

    TIMESTAMPDIFF(MICROSECOND, @t15, @t16) AS `@t16`,

    TIMESTAMPDIFF(MICROSECOND, @t16, @t17) AS `@t17`,

    TIMESTAMPDIFF(MICROSECOND, @t17, @t18) AS `@t18`,

    TIMESTAMPDIFF(MICROSECOND, @t18, @t19) AS `@t19`,

    TIMESTAMPDIFF(MICROSECOND, @t19, @t20) AS `@t20`;