Thanks for the suggestion @hubschrauber, I appreciate it. We’re looking for a more real time solution but I can see some scenarios where a polling model will work.
After more searching, and speaking specifically about Salesforce, I think the best option to control triggers in the way I need is to forego the Salesforce trigger node and use the webhook node. Then, use Salesforce Outbound Messages or HTTP callout to trigger the webhook based on the constraints. Thanks to these two posts that were really helpful in learning about those options.
Hopefully at some point the n8n team will build in the ability to add constraints/filters to the out of the box trigger nodes (for all apps, not just Salesforce) for more control.
For my organization I’d rather pay for the cloud version but limitations like this make me want to look into self-hosting so I wouldn’t have to worry about executions.