I feel the same way about not wanting to give my credentials out. I built a tool that takes all the Bank Expenses CSV exports and aggregates then I to a single CSV.

I don’t know if that’s what you’re looking for, but it may help you out.

I actually Containerized one of my CRON jobs that used rsync to copy my container volumes to my TrueNAS server (link).

I think it’s a good idea and you’ll learn a lot along the way. Plus if you open source it then it will be way easier for people to get it up and running.