There are a lot of limitations for more complex automation rules that I hit quite early exploring Jira Automation.
- Rule Size ... a rule can only have about 60 steps. Given there also is no looping, this size can be reached very quickly - even for not so complex rules
- Rule design UX ... as soon as you have mor steps in your rule than fit on a screen, the UX is a mess. You have to constantly scroll up and down in order to know where you are. This is very error prone
I have some experiences with node red, which much better supports more complex configurations without becoming a developer only tool. I suggest not to use node red as a platform but as an example to improve the current UX.
With the upcoming Confluence Automation feature I expect more automation rules and more complex rules in the near future.