You don't need a DSL if you, for example, "just" use Javascript. You need an API anyways. You do need to do some operational fudging around of course.
I'm going to also counter with something super important: you build out stuff like this, and suddenly you can handle your own feature requests faster. User wants X to happen after Y? Write a tiny event script that they install into their env. They need some bespoke field? You have custom models, and now your events reply to that.
In the fractal of requirement differences that is sales pipelines, not doing this just feels like causing yourself a bunch of dev pain.
I'm going to also counter with something super important: you build out stuff like this, and suddenly you can handle your own feature requests faster. User wants X to happen after Y? Write a tiny event script that they install into their env. They need some bespoke field? You have custom models, and now your events reply to that.
In the fractal of requirement differences that is sales pipelines, not doing this just feels like causing yourself a bunch of dev pain.