Welcome @Amazon_Rainforest
I think you’re coming into the situation with a lot of preconceived notions and expectations which seems to have lead you down a rather circuitous path.
Note DEVONthink is not a replacement for Paperless in that it’s not a bespoke receipt application nor is it Excel/Numbers. However, there are many people who have transitioned to DEVONthink and happily use it for filing their receipts and financial documents.
I would start here in a new database and examine the results. Then proceed from there…