No. As already discussed in Settlement Architecture - #3 by adrianhopebailie the external system either includes a “Settlement Engine” (the component that decides when to settle and by how much, as defined in that same thread) or not.
This changes how you design the API.
The purpose of this thread was to discuss the API for an external system that DOES NOT include settlement business logic (i.e. it’s just a ledger adaptor). If you are suggesting that this is a bad design then let’s abandon this thread and go back to Settlement Architecture - #3 by adrianhopebailie where we have all of the option properly laid out.
I’ve addressed some of your points above in that thread