MS Access / SQL Server - VBA: Upload local file to filestream on remote SQL server

I need to upload a file (<10 MB) around once a week to a SQL Server 2016 database on a remote server in the same network. Until now it was all within a Access FE/BE but I want to migrate to SQL Server as backend.

The attachments I had in MS Access so need to be handled now on the SQL database as I do not want to do this on a fileshare.

I found many threads about using something like this from SQLShack

DECLARE @File varbinary(MAX);  

SELECT  
    @File = CAST(bulkcolumn AS varbinary(max))  
FROM  
    OPENROWSET(BULK 'C:\sqlshack\akshita.png', SINGLE_BLOB) as MyData; 
 
INSERT INTO DemoFileStreamTable_1  
VALUES  (NEWID(), 'Sample Picture', @File)

This works when I start the query within SSMS on the SQL Server itself and the file is already accessible by the server on its local drive.

But when I try to put this in my VBA code on my Access frontend computer:

Sub DaoOdbcExample()
    Dim cdb As DAO.Database, qdf As DAO.QueryDef
    Set cdb = CurrentDb
    Set qdf = cdb.CreateQueryDef("")
    qdf.Connect = "ODBC;" & _
            "Driver={SQL Server};" & _
            "Server=MyServer;" & _
            "Database=MyDatabase;" & _
            "Trusted_Connection=yes;"
    qdf.SQL = "DECLARE @File varbinary(MAX); SELECT @File = CAST(bulkcolumn as varbinary(max))  FROM  OPENROWSET(BULK 'D:\SomeFile.pdf', SINGLE_BLOB) as MyData; INSERT INTO DemoFileStreamTable_1  VALUES  (  NEWID(),  'Test PDF',  @File)"
    qdf.ReturnsRecords = False
    qdf.Execute dbFailOnError
    Set qdf = Nothing
    Set cdb = Nothing
End Sub

I just get an error

ODBC--call failed

Other simple "Select" statements seem to work, so the connection itself seems okay.

So my questions are:

1. How can I perform such an upload from a local file on computer A to the remote SQL server on computer B (which cannot directly access this file) using MS Access as my frontend?

2. Is there a different way not using the "BULK" statement as I need "bulkadmin" rights for all users then?

I may have found a solution using the links from @AlwaysLearning. The first sub actually answers my question to upload a file to a remote FILESTREAM SQL Server. The second sub downloads all uploaded files into a given directory.

Private Sub btn_AddAtachment_Click()
    Dim cn, rs  As Object
    Dim sql, strCnxn, FileToUpload, FileName As String

    'FileSystemObject to do so some file checks
    Dim fso As Object
    Set fso = VBA.CreateObject("Scripting.FileSystemObject")
    
    'select file to upload, will open a FileOpenDialog
    FileToUpload = CustOpenFileDialog
    If FileToUpload <> "" Then
        FileName = fso.GetFileName(FileToUpload) 'get only filename + extension
         
        'SQL Connection
        strCnxn = "Provider=sqloledb;" & _
        "Data Source=MYSERVER;" & _
        "Initial Catalog=MYDATABASE;" & _
        "Integrated Security=SSPI;" 'Windows-Authentication
         
        Set cn = CreateObject("ADODB.Connection")
        cn.Open strCnxn
         
        'Recordset
        sql = "DemoFileStreamTable_1" 'Table to add file
        Set rs = CreateObject("ADODB.Recordset")
        rs.Open sql, strCnxn, 1, 3  '1 - adOpenKeyset, 3 - adLockOptimistic"
         
        'Create Stream to upload File as BLOB data
        Dim strm As Object
        Set strm = CreateObject("ADODB.Stream")
        strm.Type = 1 '1 - adTypeBinary
        strm.Open
        strm.LoadFromFile FileToUpload
        
        'Insert into database
        rs.AddNew 'FileId will be automatically handled by SQL
        rs!File = strm.Read
        rs!FileName = FileName
        strm.Close
        rs.Update
    End If
End Sub

Private Sub btn_DwnldSQL_Click()
    Dim cn, rs  As Object
    Dim sql As String
    Dim oStream As Object
    Dim OutputPath, strCnxn, FileName, SaveLocation As String
    
    OutputPath = "D:\ExportTest"
    
    'FileSystemObject to do so some file checks
    Dim fso As Object
    Set fso = VBA.CreateObject("Scripting.FileSystemObject")
    
    'SQL Connection
    Set cn = CreateObject("ADODB.Connection")
    strCnxn = "Provider=sqloledb;" & _
    "Data Source=MYSERVER;" & _
    "Initial Catalog=MYDATABASE;" & _
    "Integrated Security=SSPI;" 'Windows-Authentication
    
    cn.Open strCnxn 
    
    'your sql statment including varbinary max field here it is File
    sql = " SELECT [File],[FileName] from [DemoFileStreamTable_1] "
    
    'Recordset
    Set rs = CreateObject("ADODB.Recordset")
    rs.Open sql, cn
    
    'Actual Download
    Do Until rs.EOF 'Read all rows
        Set oStream = CreateObject("ADODB.Stream")
        FileName = CStr(rs.Fields("FileName").Value) 'FileName from Database field
        SaveLocation = fso.BuildPath(OutputPath, FileName) 'Create outputpath
        With oStream
             .Type = 1 '1 - adTypeBinary
             .Open
             .Write rs.Fields("File").Value 'actual BLOB data
             .SaveToFile SaveLocation, 2 '2 - adSaveCreateOverWrite
             .Close
        End With
        Set oStream = Nothing
        rs.MoveNext
    Loop
    rs.Close
    cn.Close
End Sub

Function CustOpenFileDialog() As String 
    Const msoFileDialogFilePicker As Long = 3
    Dim objDialog As Object
    Set objDialog = Application.FileDialog(msoFileDialogFilePicker)
    Dim fso As Object
    Set fso = VBA.CreateObject("Scripting.FileSystemObject")
    Dim FileName As String

    With objDialog
        .AllowMultiSelect = False
        ' Set the title of the dialog box.
        .Title = "Please select one file"
        ' Clear out the current filters, and add our own.
        .Filters.Clear
        .Filters.Add "supported Types", "*.pdf, *.xml, *.gltf, *.jpg, *.png"
 
        ' Show the dialog box. If the .Show method returns True, the
        ' user picked at least one file. If the .Show method returns
        ' False, the user clicked Cancel. 
        If .Show = True Then
            CustOpenFileDialog = .SelectedItems(1)
        Else
            CustOpenFileDialog = ""
        End If
    End With
End Function