Optimize Query performance, Cross Join balances on Calendar table

I have a query that theoretically works but in practice doesn't have the performance to do the job. The idea is to get the week balance for column MTNSTT(quantity balance) within table INFORM3_M3FDB_MITTRA. However this is a transaction table, and sometimes there aren't any transactions for an entire month for certain articles. So there are gaps in the balance for which I came with the idea to use a CROSS JOIN on a Calendar Table, to find the LAST BALANCE closest to the End of the Week_ISO date, per Article (and other important fields regarding locations.

EDIT: https://pastebin.com/5V48sfb3 XML Execution Plan of Query, here only for a subset of the data, since the entire query never loads. It is somehow too heavy.

So, very oversimplified, just for the idea, instead of having This data:

| MTNSTT | MTTRGDT  |
|--------|----------|
| 100    | 20220101 |
| 150    | 20220115 |
| 75     | 20220204 |

I have this data now available in current solution with the Calendar Table:

| MTNSTT | CALENDAR_ID |
|--------|-------------|
| 100    | 20220102    |
| 100    | 20220109    |
| 150    | 20220116    |
| 150    | 20220123    |
| 150    | 20220130    |
| 75     | 20220206    |

The following three tables are being used:

ODS.INFORM3_M3FDB_FCAAVP with ~11 million records
ODS.INFORM3_M3FDB_MITTRA with ~33 million records
ODS.INFORM3_M3FDB_MITBAL with ~16 million records

The query retrieves the following error while loading overnight:

A severe error occurred on the current command. The results, if any, should be discarded.

The query looks as follows, it does the job, but I assume it is a performance related issue. I use the transaction table MITTRA twice, because I need two fields per week MTNSTT(balance of quantity) and MTTRPR (price). And I use a similar transaction table INFORM3_M3FDB_FCAAVP to get A7APPR (corrected price). All date columns in the query are YYYYMMDD INT data types.

SELECT
    CALENDAR_ID
    ,WEEKDAY_ISO
    ,YYYYMM
    ,MBITNO --Article
    ,MBWHLO --Wharehouse
    ,MBFACI --Facility
    ,MBCONO --Company number
    ,MBWHSL --Wharehouse Location
    ,MBDIVI --Division
    ,(SELECT TOP 1 MTNSTT FROM ODS.INFORM3_M3FDB_MITTRA MITTRA
                WHERE MITTRA.IsCurrent = 1  
                    AND MTTRDT <= CALENDAR_ID
                    AND MTITNO = MBITNO
                    AND MTWHLO = MBWHLO
                    AND MTCONO = MBCONO
                    AND MTWHSL = MBWHSL
                ORDER BY CONCAT(MTTRDT,MTTRTM,MTTMSX) DESC) AS [Quantity] 
--The order by includes Date, Time and Timesuffix, 
--necessary in the order by to get latest balance on specific date
    ,(SELECT TOP 1 MTTRPR FROM ODS.INFORM3_M3FDB_MITTRA MITTRA
                WHERE MITTRA.IsCurrent = 1  
                    AND MTTRDT <= CALENDAR_ID
                    AND MTITNO = MBITNO
                    AND MTWHLO = MBWHLO
                    AND MTCONO = MBCONO
                    AND MTWHSL = MBWHSL
                ORDER BY CONCAT(MTTRDT,MTTRTM,MTTMSX) DESC) AS [Price]
    ,(SELECT TOP 1 A7APPR FROM ODS.INFORM3_M3FDB_FCAAVP
                WHERE IsCurrent = 1 
                    AND A7RGDT <= CALENDAR_ID
                    AND A7ITNO = MBITNO
                    AND A7FACI = MBFACI
                    AND A7WHLO = MBWHLO
                    AND A7CONO = MBCONO
                ORDER BY A7LMTS DESC) AS [Corrected_Price] 
--A7LMTS is the date including timestamp
FROM ODS.CALENDAR C
CROSS JOIN (SELECT DISTINCT MBITNO, MBWHLO, MBFACI, MBCONO, MBWHSL, MBDIVI FROM ODS.INFORM3_M3FDB_MITBAL) MITBAL 
WHERE CALENDAR_ID <= YEAR(GETDATE())*10000
--WHERE LEFT(CALENDAR_ID,4) <= YEAR(GETDATE())
AND WEEKDAY_ISO = 7 --Here I drop everything except the Sundays, to only have Week balances 

I use the following indexes, all fields I used in JOIN / ORDER BY exist in them:

CREATE NONCLUSTERED INDEX [NCL_IX_INFORM3_M3FDB_MITTRA_Balance] ON [ODS].[INFORM3_M3FDB_MITTRA]
(
    [MTCONO] ASC,
    [MTWHLO] ASC,
    [MTWHSL] ASC,
    [MTITNO] ASC,
    [MTRGDT] ASC,
    [MTRGTM] ASC,
    [MTTRDT] ASC,
    [MTTRTM] ASC,
    [MTTMSX] ASC,
    [IsCurrent] ASC
)
INCLUDE([MTRSCD],[MTTRPR],[MTTRQT]) WITH (STATISTICS_NORECOMPUTE = OFF, DROP_EXISTING = OFF, ONLINE = OFF, OPTIMIZE_FOR_SEQUENTIAL_KEY = OFF) ON [PRIMARY]
GO

CREATE NONCLUSTERED INDEX [NCL_IX_INFORM3_M3FDB_MITBAL_Balance] ON [ODS].[INFORM3_M3FDB_MITBAL]
(
    [MBCONO] ASC,
    [MBWHLO] ASC,
    [MBWHSL] ASC,
    [MBFACI] ASC,
    [MBITNO] ASC,
    [IsCurrent] ASC
)
INCLUDE([MBDIVI],[MBSUNO]) WITH (STATISTICS_NORECOMPUTE = OFF, DROP_EXISTING = OFF, ONLINE = OFF, OPTIMIZE_FOR_SEQUENTIAL_KEY = OFF) ON [PRIMARY]
GO

CREATE NONCLUSTERED INDEX [NCL_IX_INFORM3_M3FDB_FCAAVP_Balance] ON [ODS].[INFORM3_M3FDB_FCAAVP]
(
    [A7CONO] ASC,
    [A7FACI] ASC,
    [A7ITNO] ASC,
    [A7RGDT] ASC,
    [A7WHLO] ASC,
    [A7TMSX] ASC,
    [IsCurrent] ASC
)WITH (STATISTICS_NORECOMPUTE = OFF, DROP_EXISTING = OFF, ONLINE = OFF, OPTIMIZE_FOR_SEQUENTIAL_KEY = OFF) ON [PRIMARY]
GO

The estimated query plan: