specifying linked server

I see this question was asked long ago and probably everybody's solved it by now, but I couldn't find any direct answers posted. Here are several M snippets that pull data through SQL Server via Linked Servers with Joins in M. In the examples, Linked Server LS_Proto is targeted to an Excel Workbook, and I'm pulling data from named ranges but of course these can be hacked to pull from different sources. I'm illustrating use of LS with several M data functions. And while we're pulling data thru SQL Server from external sources, showed use of OPENROWSET too.

Using OleDb.DataSource, with Linked Server Query, to get and join from Excel Named Ranges
let
xlAlloc=OleDb.DataSource("Provider=MSOLEDBSQL; initial catalog=ExcelProto; data source=MYSERVER\SQLEXPRESS", [Query="SELECT * FROM LS_Proto...rngAlloc"]),
xlBOM=OleDb.DataSource("Provider=MSOLEDBSQL; initial catalog=ExcelProto; data source=MYSERVER\SQLEXPRESS", [Query="SELECT * FROM LS_Proto...rngBOM"]),
AB=Table.Join(xlAlloc, {"akAllocRevKey"},xlBOM,{"bmBOMItemKeyIn"},JoinKind.LeftOuter),
in
AB

Using OleDb.Query, with Linked Server Query, to get and join Excel Named Ranges
let
FileSource = "Provider=MSOLEDBSQL; initial catalog=ExcelProto; data source=MYSERVER\SQLEXPRESS",
xlAlloc = OleDb.Query(FileSource,"SELECT * FROM LS_Proto...rngAlloc"),
xlBom = OleDb.Query(FileSource,"SELECT * FROM LS_Proto...rngBOM"),
AB=Table.Join(xlAlloc, {"akAllocRevKey"},xlBOM,{"bmBOMItemKeyIn"},JoinKind.LeftOuter),
in
AB

Using OleDb.DataSource, with OPENROWSET Query, to get and join Excel Named Ranges
let
xlAlloc=OleDb.DataSource("Provider=MSOLEDBSQL; initial catalog=ExcelProto; data source=MYSERVER\SQLEXPRESS", [Query="SELECT * FROM OPENROWSET('Microsoft.ACE.OLEDB.12.0','Excel 12.0; Database=C:\filepath\File.xlsm;HDR=YES', rngAlloc)"]),
xlBOM=OleDb.DataSource("Provider=MSOLEDBSQL; initial catalog=ExcelProto; data source=MYSERVER\SQLEXPRESS", [Query="SELECT * FROM OPENROWSET('Microsoft.ACE.OLEDB.12.0','Excel 12.0; Database=C:\filepath\File.xlsm;HDR=YES', rngBOM)"]),
AB=Table.Join(xlAlloc, {"akAllocRevKey"},xlBOM,{"bmBOMItemKeyIn"},JoinKind.LeftOuter),
in
AB