Ah - Just so you're aware I've just gone through the same steps as you and yes, I see exactly what you mean.
Unfortunately It appears there's no obvious way to supply additional parameters in the catalogue so I feel we may be at a roadblock at this particular angle. I know programmatically there's nothing preventing you passing in those additional credentials into a query/script - but the UI seems to be a blocker on this one.

Hopefully someone who knows a little more about this side can chime in with a solution. It could also be one for the ideas section:
https://docs.databricks.com/aws/en/resources/ideas as I feel you can't be the only one with this query!

Do you know if you're able to install an older version of the JDBC driver as mentioned previously? I wonder if that would perform differently.