Hi Jim,
Does this mean that only hosted feature layers in an Enterprise can be used with Power Automate webhooks?
You can create webhooks on Hosted feature layers in ArcGIS Enterprise. This means when you publishing data to your enterprise from ArcGIS Pro, you are selecting `Copy all data` option. If you select `Reference registered data` (meaning you are referencing a data from Enterprise geodatabase) web hooks created on resulting Feature layer are currently not supported.

Or does your bullet point only apply to feature layers and map services shared from Enterprise to ArcOnline?
I am not sure what you mean.
Can I use the Power Automate Connection for my Enterprise 11.3 in conjunction with the Power Automate Enterprise triggers that utilize webhooks such as "When a record is created in a feature layer" or "When a record is updated in a feature layer" with data published from an Enterprise geodatabase?
You can use all the triggers as long as it is not referencing registered data from in ArcGIS Enterprise.
We have fixed it will be rolled out when Microsoft releases it!
Hope that helps.
Thanks,
Akshay Harshe