[purerandomness]

> OP isn't selling things directly to end-users

That's ridiculous. If you provide a whitelabel solution, you simply add consent checkboxes and and explanatory text, the same way shop systems and virtually all other whitelabel software meant to be embedded works.

> how culpable OP is for abuse of his tool's abilities

Regulators don't care where you sourced the software from that you provided. You provide it, you host it, you're culpable.