A: Awesome! I've just looked into them all and Activepieces for now looks very promising.

I've written them down on our "Zapier Integration" feature request:
https://collabwriting.sleekplan.app/feedback/86219/

We'll look more into it. I assume that when we figure out everything around integrating with Zapier we'll be able to develop an alternative pretty fast 😄

What I like about Activepieces is that it's open source so it can be easily maintainable by us in the future. Thanks for sharing, and we'll keep you posted 😄