Creating a waterfall not using dates and resetting middle of graph to zero

Hi,Tommy123 .I am glad to help you.
Assuming your real data is as follows
 

You want to add a row of reset data to zero out the data in the waterfall chart.

The effect is shown in the waterfall visual:

If you only need to ensure that the presentation effect changes in the waterfall diagram without affecting the rest of the visual.
Creating a new calculation table using DAX is a good option

My Dax Code:

Use the UNION function to achieve data splicing (the number of column fields and column names are the same)
Use the RANKX function to generate a ranking sequence (the last parameter is changed from DENSE to SKIP to ensure that the same rank is not displayed for the same data)

AdjustedTableDAX = 
VAR OriginalTable = 
    ADDCOLUMNS(
        'waterfallTest',
        "CumulativeValue", 
        SUMX(
            FILTER(
                'waterfallTest',
                'waterfallTest'[Order] <= EARLIER('waterfallTest'[Order])
            ),
            'waterfallTest'[Value]
        )
    )
VAR ResetRow = 
    SELECTCOLUMNS(
        FILTER(
            OriginalTable,
            'waterfallTest'[Catergory] = "Discount 2"
        ),
        "Catergory", "Reset",
        "Value", -[CumulativeValue],
        "Order", [Order] + 1,
        "CumulativeValue", BLANK()  -- Ensure the same number of columns
    )
VAR AdjustedTable = 
    UNION(
        SELECTCOLUMNS(
            FILTER(
                OriginalTable,
                'waterfallTest'[Order] <= 3
            ),
            "Catergory", [Catergory],
            "Value", [Value],
            "Order", [Order],
            "CumulativeValue", [CumulativeValue]
        ),
        ResetRow,
        SELECTCOLUMNS(
            FILTER(
                OriginalTable,
                'waterfallTest'[Order] > 3
            ),
            "Catergory", [Catergory],
            "Value", [Value],
            "Order", [Order] + 1,  -- Adjust the order for subsequent rows
            "CumulativeValue", [CumulativeValue]
        )
    )
RETURN
    SELECTCOLUMNS(
        ADDCOLUMNS(
            AdjustedTable,
            "NewOrder", RANKX(AdjustedTable, [Order], , ASC, DENSE)
        ),
        "Catergory", [Catergory],
        "Value", [Value],
        "Order", [NewOrder]
    )

If you want to do additional calculations (create new measure/calculate columns) while modifying the format of the table
It is also a good idea to use M code to create a new table.

This is my M code:

let
    Source = Excel.Workbook(File.Contents("C:\Users\username\Desktop\test_1_14.xlsx"), null, true),
    waterfallTest_Sheet = Source{[Item="waterfallTest",Kind="Sheet"]}[Data],
    #"Promoted Headers" = Table.PromoteHeaders(waterfallTest_Sheet, [PromoteAllScalars=true]),
    #"Changed Type" = Table.TransformColumnTypes(#"Promoted Headers",{{"Catergory", type text}, {"Value", Int64.Type}, {"Order", Int64.Type}}),
    #"Added Index" = Table.AddIndexColumn(#"Changed Type", "Index", 1, 1, Int64.Type),
    #"Added Cumulative" = Table.AddColumn(#"Added Index", "CumulativeValue", each List.Sum(List.FirstN(#"Added Index"[Value], [Index]))),
    #"Reset Row" = #table(
        {"Catergory", "Value", "Order", "CumulativeValue", "Index"},
        {{"Reset", -#"Added Cumulative"{2}[CumulativeValue], 4, -#"Added Cumulative"{2}[CumulativeValue], 4}}
    ),
    #"Inserted Reset" = Table.Combine({Table.FirstN(#"Added Cumulative", 3), #"Reset Row", Table.Skip(#"Added Cumulative", 3)}),
    #"Removed Existing Cumulative" = Table.RemoveColumns(#"Inserted Reset",{"CumulativeValue", "Order", "Index"}),
    #"Added Index1" = Table.AddIndexColumn(#"Removed Existing Cumulative", "Order", 1, 1, Int64.Type),
    #"Changed Type1" = Table.TransformColumnTypes(#"Added Index1",{{"Value", type number}})
in
    #"Changed Type1"

I hope my suggestions give you good ideas, if you have any more questions, please clarify in a follow-up reply.
Best Regards,
Carson Jian,
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