Maybe ticket isn't a great example. Another general problem I've had with mappings is say, one service uses a one-to-one relationship, and another puts both entities into a single entity. E.g., maybe there's a way to share tickets externally. One allows you to create a shareable link as a separate entity, and another embeds the shareable link as a property of the ticket.

I think, looking at this, I'd still probably prefer to create something custom. What would really help is simplifying having to set up OAuth and api calls, and just being able to do the mapping (or transform, of extract-transform-load) myself, in case there are edge-cases.