sql dynamic pivot where clause failing

Question

I am trying to figure out where my query is failing on a where clause, I hope some of the local experts could point it out and explain why. Also I would like to add a total to the end of the query but mainly need to get the where clause to work!

If I do this query by itself it works the way I want:

 select
    JobCode,
    DepartmentName,
    (COALESCE(MonTime, 0)+COALESCE(TueTime, 0)+COALESCE(WenTime, 0)+COALESCE(ThurTime, 0)+COALESCE(FriTime, 0)
                +COALESCE(SatTime, 0)+COALESCE(SunTime, 0)) as total
    
from TimeSheetTable

INNER JOIN DepartmentTable ON TimeSheetTable.DeptId=DepartmentTable.Id
inner join  JobCodeTable on TimeSheetTable.JobId=JobCodeTable.Id


where  WeekStartDate  Between '2022-04-11' and '2022-04-25'

When I add the query to be pivoted I am getting this error:

Msg 207, Level 16, State 1, Line 16 Invalid column name '2022-04-11'. Msg 207, Level 16, State 1, Line 16 Invalid column name '2022-04-11'.

The table:

CREATE TABLE [dbo].[TimeSheetTable]
(
    [Id] INT NOT NULL PRIMARY KEY IDENTITY, 
    [WeekStartDate] DATE NOT NULL, 
    [MonTime] FLOAT NULL, 
    [TueTime] FLOAT NULL, 
    [WenTime] FLOAT NULL, 
    [ThurTime] FLOAT NULL, 
    [FriTime] FLOAT NULL, 
    [SatTime] FLOAT NULL, 
    [SunTime] FLOAT NULL, 
    [EmpID] INT NOT NULL, 
    [JobId] INT NOT NULL,
    [DeptId] INT NOT NULL, 
    [Comments] NVARCHAR(MAX) NULL, 

    CONSTRAINT [FK_TimeSheetTable_JobTable] 
        FOREIGN KEY ([JobId]) REFERENCES [JobCodeTable]([Id]),
    CONSTRAINT [FK_TimeSheet_Emp] 
        FOREIGN KEY ([EmpID]) REFERENCES [EmployeeTable]([Id]),
    CONSTRAINT [FK_TimeSheetTable_Department] 
        FOREIGN KEY ([DeptId]) REFERENCES [DepartmentTable]([Id])
)

The query that throw the error:

--get row names
DECLARE 
    @departments NVARCHAR(MAX) = '', 
    @sql     NVARCHAR(MAX) = '';

-- select the category names
SELECT 
    @departments += QUOTENAME(DepartmentName) + ','
FROM 
    DepartmentTable
ORDER BY 
    DepartmentName;

-- remove the last comma

SET @departments = LEFT(@departments, LEN(@departments) - 1);

--get columns
--PRINT @columns;
-- construct dynamic SQL
SET @sql ='
SELECT * FROM 
(
   select
    JobCode,
    DepartmentName,
    (COALESCE(MonTime, 0)+COALESCE(TueTime, 0)+COALESCE(WenTime, 0)+COALESCE(ThurTime, 0)+COALESCE(FriTime, 0)
                +COALESCE(SatTime, 0)+COALESCE(SunTime, 0)) as total
    
from TimeSheetTable
INNER JOIN DepartmentTable ON TimeSheetTable.DeptId=DepartmentTable.Id
inner join  JobCodeTable on TimeSheetTable.JobId=JobCodeTable.Id
--getting error here--
where  WeekStartDate  Between "2022-04-11" and "2022-04-25"
    
) t 
PIVOT(
   sum(total)
   FOR DepartmentName IN ('+ @departments +')
)pivot_table
ORDER BY JobCode
'
---- execute the dynamic SQL
EXECUTE (@sql);

This is what I have to work with but not my design I need to get a date range and fairly new to SQL! Eventually I would like to make it into a stored procedure and put in variables in the where clause, just using the dates hard coded now