Creating While Loop with Multiple Conditions

I understand that this type of procedure is NOT preferable nor efficient, but I am at a point where this type of table is needed since I have not been able to get a response to my original question (Fill In for Null Values for Date, Product Code & QTY) on here. I found this relevant post/answer (While loop with multiple conditions in T-SQL) but need it adapted to my scenario. As I am only a data-querying guy I haven't a clue what I am doing in this while begin loop that I failed to BM where I drafted it from.

I am in the same scenario as the user in the aforementioned post, I don't want to have to create this type of table but am out of options and help. Am very much hoping I can get some help/answers as the user above did.

Help me ObiOneOverflow, you're my only hope!

I am trying to create a daily reference record for each product code between two dates, looping on the ROWID till it gets to the last ROWID integer. It is breaking somewhere, I just don't have the experience in this type of programming to figure out why nor where, I HAVE tried changing parts to see how it reacts, but never getting a successful run.

I hope you pros can simply see where I'm causing it to fail on a loop and keep iterating up between the dates, then restarting on the next ROWID from the product table.

    CREATE TABLE FACT_ECODEMONTHLY
        ( 
            STARTDT DATE NOT NULL,
            MONTHEND DATE NOT NULL,
            ECODE VARCHAR (255)
        );

    DECLARE @STARTDT DATE
    DECLARE @ENDDT DATE
    DECLARE @TEMPDT DATE
    DECLARE @START INT
    DECLARE @END INT
    DECLARE @TEMPNO INT
    DECLARE @ROWID INT
    DECLARE @ECODE VARCHAR (255)

    SET @STARTDT = '2017-01-01'
    SET @ENDDT = '2022-12-31'
    SELECT @START = MIN(DE1.ROW_ID), @END = MAX(DE1.ROW_ID) FROM DIM_ECODES DE1 
    SET @ECODE = ( SELECT DE2.ECODE FROM DIM_ECODES DE2 WHERE ROW_ID = @START )

    BEGIN

        WHILE (@STARTDT <= @ENDDT) AND (@START <= @END )
            BEGIN
                SET @TEMPDT = @STARTDT;
                SET @TEMPDT =  DATEADD( DAY , 1 , @TEMPDT)

        WHILE (@START <= @END )
            BEGIN 
                SET @TEMPNO = @START;
                SET @TEMPNO = @TEMPNO + 1

        INSERT INTO FACT_ECODEMONTHLY 
        ( STARTDT ,  MONTHEND , ECODE ) 

                VALUES 
                    ( @STARTDT , EOMONTH(@STARTDT) , @ECODE )

                    IF (@STARTDT <= @ENDDT )
                    BEGIN
                        SET @STARTDT = @TEMPDT
                    END
                    ELSE
                    BEGIN
                        SET @STARTDT = '2017-01-01'
                        SET @ENDDT = DATEADD (DAY , 1 , @STARTDT)
                    END

                    IF (@START <= @END)
                    BEGIN
                        SET @START = @TEMPNO
                    END
                    ELSE
                    BEGIN
                        SET @START = 1
                        SET @END = @START + 1
                    END

            END
            END
    END

When I run the above, I get the following:

How it processes

What it produces

Thank you for looking and any assistance provided.

Schema (MySQL v8.0)

CREATE TABLE DIM_ECODES
    (

        ECODE VARCHAR(255) NOT NULL,
        MCODE VARCHAR(255) NOT NULL,
        SOURCE VARCHAR(255) NOT NULL,
        ROW_ID INT

    );

INSERT INTO DIM_ECODES

    (ECODE , MCODE , SOURCE , ROW_ID )
    
 VALUES
 
('Q5142-80','Q5999-571','TEAM',1),
('P1DH6-','P1DH6-', 'TEAM',2),
('U616Z-051','U520U-','TEAM',3),
('14404-31','14404-31', 'TEAM',4),
('R6980-','R6980-', 'TEAM',5);

Query #1

SELECT *

FROM DIM_ECODES;

View on DB Fiddle

DESIRED RESULTS EXAMPLE