A fallback I guess I tend to look at whenever something stops being “natively” read by a vendor’s platform is to use Windows as the data broker through ODBC.

So in FME, an ODBC Reader with an ODBC DSN configured on the machine using one of the CouchDB ODBC drivers?

I dont think ill be able to install software on that machine. Ill try.

ODBC driver installation happens on the client machine end, not the server.  Typically on the same machine as FME.

Couchbase points to these drivers as the recommended for install on the PC/machine making the queries such as the FME machine.
https://www.cdata.com/drivers/couchdb/odbc/

Steps for setting up on the PC/machine for configuring an ODBC DSN in Windows or Linux and how then to connect from various Eg. Windows applications on that PC are below.

The documentation suggest all that is needed for config on the PC ODBC connection is the CouchDB Web URL and your User Name and Password.  This in theory then when connect to the saved ODBC DSN file etc. that get out of the ODBC Setup Wizard, in FME will get presented with a list of CouchDB tables etc. for reading if going via a Reader, and it appears it may even parse SQL if interface instead go through something like SQLCreator.

https://cdn.cdata.com/help/JCH/odbc/default.htm

https://cdn.cdata.com/help/JCH/odbc/pg_usageo.htm

Optionally it appears can also run at an Enterprise level a single SQL Gateway machine using the same vendor’s Tools (can live on the same machine as FME or be remote) a virtual MySQL database as well that is running a MySQL Service that is using the ODBC connectivity to CouchDB in the backend.  But that would probably only be if need for multiple users to query CouchDB as harder to initially setup but makes it easier then for multi-users to connect to single MySQL service.