How to calculate dates using start and end date distribute per month

OK, here is a method using Power Query M Code (which I just happened to develop earlier for a similar problem).

Home =>Trnasform data=>Advanced Editor  and paste the code into the window that opens (deleting whatever might be there)

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMlTSUTLUN9I3MjAyAjONYUy/1HKFyPyibKVYHZgyU5hcXmlODroSkDjQHLhRQIY5jB2Sn52ZD1dljKTKBImNqgooA7fPXB9dUSwA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [IncidentID = _t, #"Lost work start" = _t, #"lost work end" = _t, Location = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"IncidentID", Int64.Type}, {"Lost work start", type date}, {"lost work end", type date}, {"Location", type text}}),

//Create all months list
    #"Last Day" = Date.From(DateTime.FixedLocalNow()),
    #"all Dates" = 
        List.Dates(
            List.Min(#"Changed Type"[Lost work start]),
            Duration.Days(#"Last Day"-List.Min(#"Changed Type"[Lost work start])) + 1,
            #duration(1,0,0,0)),
    #"all MnthYr" = List.Distinct(List.Transform(#"all Dates", each Date.ToText(_,"yyyy-MM"))),

//List of Dates for each row
    #"Days per Month" = Table.AddColumn(#"Changed Type", "Dates List", each 
        let 
            LWD = 
                List.Dates(
                    [Lost work start],
                    Duration.Days(List.Min({[lost work end], #"Last Day"}) - [Lost work start]) + 1,
                    #duration(1,0,0,0)),
            MnthYr = List.Transform(LWD, each Date.ToText(_,"yyyy-MM")),
    
        //Group by MnthYr and count
            Group = Table.Group(Table.FromColumns({MnthYr} & {LWD}),{"Column1"},{
                {"Days in Month", each Table.RowCount(_), Int64.Type}}),
            Pivot = Table.Pivot(Group,List.Sort(Group[Column1]),"Column1","Days in Month")
        in 
            Pivot),
    #"Expanded Dates List" = Table.ExpandTableColumn(#"Days per Month", "Dates List", #"all MnthYr"),

    #"Sort Month/Year Columns" = 
        let 
            colsToSort = List.RemoveFirstN(Table.ColumnNames(#"Expanded Dates List"),4),
            #"Sorted Order" = List.Sort(colsToSort),
            #"Reorder Columns" = Table.ReorderColumns(#"Expanded Dates List",#"Sorted Order")
        in 
            #"Reorder Columns",

    #"Month To Name" = Table.RenameColumns(#"Sort Month/Year Columns",
        List.Transform(List.RemoveFirstN(Table.ColumnNames(#"Sort Month/Year Columns"),4), each{_, Date.ToText(Date.From(_),"MMM-yy")})),
    #"Grouped Rows1" = Table.Group(#"Month To Name", {"Location"}, {

       //Sum each month
        {"Sum Each Month", (t)=> Record.FromList(
            
                List.Accumulate(List.RemoveFirstN(Table.ColumnNames(t),4),{}, (a,b)=>
                    a & {List.Sum(Table.Column(t,b))}), List.RemoveFirstN(Table.ColumnNames(t),4))
        }}),
    #"Expanded Sum Each Month" = Table.ExpandRecordColumn(#"Grouped Rows1", "Sum Each Month", 
        List.RemoveFirstN(Table.ColumnNames(#"Month To Name"),4)),
        
    #"Typed" = Table.TransformColumnTypes(#"Expanded Sum Each Month", 
                    List.Transform(List.RemoveFirstN(Table.ColumnNames(#"Expanded Sum Each Month")), each {_, Int64.Type}))
in
    #"Typed"

Results: