Can LATERAL JOIN have a pivot table subquery in MariaDB 10.6?

Question

I am trying to join data from two tables by nearest earliest date. The first tables dates are more frequent than the seconds dates. I came across a few links and it seems like a Lateral Join may provide what I need:

1. https://jonmce.medium.com/what-the-heck-is-a-lateral-join-anyway-4c3345b94a63
2. SQL: join with an equal key and nearest key (similar to Pandas's merge as of)

The first table, (Table A) and is the correct dimension i.e number of rows.

date	code	multiplier
2018 - 01 -01	c1	.3
2018 - 01 -01	c2	.5
2018 - 01 -01	c3	.2
2018 - 06 -01	c1	.4
2018 - 06 -01	c1	.4
2018 - 06 -01	c3	.2
2019 - 01 -01	c1	1
2019 - 06 -01	c1	.5
2019 - 06 -01	c2	.5
2020 - 01 -01	c1	.3
2020 - 01 -01	c2	.5
2020 - 01 -01	c3	.2

However, the second table needs to be pivoted before it can be mapped on the first table.

date	Item	cost
2018 - 01 -01	A	1
2018 - 01 -01	B	2
2018 - 01 -01	C	2
2019 - 01 -01	A	2
2019 - 01 -01	B	3
2019 - 01 -01	C	4
2020 - 01 -01	A	4
2020 - 01 -01	B	4
2020 - 01 -01	C	5

My attempt at using LATERAL JOIN...

SELECT 
  A.*, C.*
FROM ( 
   SELECT
         `j`.`id`,
         `j`.`date`,
         `k`.`key`,
         `k`.`value`
   FROM `j`
       INNER JOIN `k` ON `j`.`id` = `k`.`id`
       WHERE `j`.`guid` = '<filter>'
) AS A
LEFT JOIN LATERAL (
   SELECT `B`.*
   FROM (
         SELECT
         'rate'.`date`,
         MIN( CASE WHEN `rate`.`item` = 'itemA' THEN `rate`.`cost` END) 'itemA',
         MIN( CASE WHEN `rate`.`item` = 'itemB' THEN `rate`.`cost` END) 'itemB',
         MIN( CASE WHEN `rate`.`item` = 'itemC' THEN `rate`.`cost` END) 'itemC'
         FROM `rate`
         GROUP BY `rate`.`date`) AS B
   WHERE `B`.`date` <= `A`.`date`
   ORDER BY `B`.`date` DESC LIMIT 1) AS `C` ON true
);

The result should just have the values of the pivoted tables new columns with some duplication. But I am getting a syntax error Schema Error: Error: ER_PARSE_ERROR: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '( SELECT B.* FROM ( SELECT 'rate'.date, MIN'

date	code	multiplier	A	B	C	date2
2018 - 01 -01	c1	.3	1	2	2	2018-01-01
2018 - 01 -01	c2	.5	1	2	2	2018-01-01
2018 - 01 -01	c3	.2	1	2	2	2018-01-01
2018 - 06 -01	c1	.4	1	2	2	2018-01-01
2018 - 06 -01	c2	.4	1	2	2	2018-01-01
2018 - 06 -01	c3	.2	1	2	2	2018-01-01

I pretty sure I can do this using python and pandas or spark, but I'd prefer to keep this in SQL and I like the cleanliness of the Lateral Join. I do know that table 1 (A) works and so does Table B (The pivot). The issue is putting table B inside of the Lateral Join is where my issue is arising.