Write from Postgres to SQL Server

I find myself in an environment wanting to move to Postgres, having a variety of smaller Postgres databases, but the business currently revolves around a “God” SQL Server database.

I’m looking for general advice about making the two work together.

More specifically, interoperating between the two would be a good deal easier if I have write access from Postgres to SQL Server.

An obvious possibility is to write to SQL Server in a Postgres stored procedure/trigger using code written in Python or whatever, using the facilities native to that language. An obvious issue that arises then is whether I can maintain a persistent connection to SQL Server (assuming that connection setup takes appreciable time).

I am also interested to know if the SQL Server FDW extension works reliably, or any other advice folks may have.

Thanks in advance.