Look awesome, and although the license is definitely NOT open source (although you DO say the parts that people care the most are best-effort open source to the community), this has the potential to motivate other people to work on similar projects or suggest improvements to yours.
However... The beauty of Zapier relies on its amount of pluggable blocks. I don't think there's anyone in this market that has as many operations as Zapier and using custom blocks you can do pretty much anything. Yes I am totally a fan of Zapier as I have been using it for years! Zapier is like LEGO, there are many clones of LEGO but only one true LEGO (ouch my feet hurt just by thinking about it ;) ) I really hope you can get people to contribute more and more integrations as that's what really matters at the end of the day: The ability to use little or no-code to achieve automation between various platforms!