You could add support for something like simplefin.org, which provides an API for connecting to many different financial orgs. It is what I have been using for my local setup with Actual budget.

Actual budget is good. Connectivity in Australia sucks though so I've kludged my own approach (open banking connections to a single local aggregator then puppeteer to sign in and get an access token, then directly calling the aggregators internal APIs with it and pushing the data into a local Actual server using Actual's APIs).

Does your financial orgs actually support simplefin or are you using simplefin bridge?

Bridge is actually provided by mx.com, pretty much the same service as Plaid.

Thanks, will surely look into this.