MariaDB writing transaction and rollback - novice

Currently I am learning how to write transactions for MariaDB (I got a version 10.6 running). I attempt to execute several commands and based on their success to commit or rollback. So far I have searched google for a few days and got really stuck not knowing how to go about it. This is how far I got and cannot figure out what is wrong. I am very grateful for any pointers! Cheers
JR

DROP TABLE IF EXISTS FWtest.testtrans;
CREATE TABLE FWtest.testtrans ( 
	ID INT NOT NULL AUTO_INCREMENT , 
	ver INT NULL DEFAULT NULL , 
	name VARCHAR(10) NULL DEFAULT NULL , 
	savedatetime DATETIME NULL DEFAULT NULL , 
PRIMARY KEY (ID)) ENGINE = InnoDB;

DROP TABLE IF EXISTS FWtest.testtrans2;
CREATE TABLE FWtest.testtrans2 ( 
	ID INT NOT NULL , 
	param1 INT NULL DEFAULT NULL , 
	param2 INT NULL DEFAULT NULL)
ENGINE = InnoDB;



DELIMITER |
START TRANSACTION
	BEGIN NOT ATOMIC TRY;
		SET @config_name='test';
        -- get the next version number, set 0 if none
		SELECT @config_version:= IFNULL(max(ver)+1,0) FROM FWtest.testtrans WHERE name = @config_name;
		INSERT INTO FWtest.testtrans(name, ver, savedatetime) 
          VALUES ( @config_name, @config_version, NOW() );
		
		SELECT @config_id:=LAST_INSERT_ID();
		
		INSERT INTO FWtest.testtrans2(ID, param1, param2) 
		  VALUES 
		    (@config_id, 1, null),
		    (@config_id, 2, 'aa');	-- this line will make the insert fail
		
	END TRY
	BEGIN CATCH
		ROLLBACK;
	END CATCH
COMMIT|
DELIMITER ;

**SOLUTION:** Thanks to the pointers of Akina I worked out a solution using an exception handler directly in a transaction:

DELIMITER |
BEGIN NOT ATOMIC
	DECLARE EXIT HANDLER FOR SQLEXCEPTION ROLLBACK;
	START TRANSACTION;
			SET @config_name='test';
			SELECT @config_version:= IFNULL(max(ver)+1,0) FROM FWtest.testtrans WHERE name = @config_name;
			INSERT INTO FWtest.testtrans(name, ver, savedatetime) VALUES ( @config_name, @config_version, NOW() );
			
			SELECT @config_id:=LAST_INSERT_ID();
			
			INSERT INTO FWtest.testtrans2
			(ID, param1, param2) 
			VALUES 
			  (@config_id, 1, null),
			  (@config_id, 2, 'nn');	-- this line will make the insert fail
			
	
	COMMIT;
END|
DELIMITER ;

Note: When using this sample code in a sql tool (e.g. DBeaver) then error checking and rollback needs to be turned off in order for the transaction to handle the error itself.