Thanks for reaching out, hopefully we can assist.
Does Google Site Kit fully support GA4?
At present the Google Analytics 4 can be implemented within Site Kit by using Google Tag Manager. The Analytics module within Site Kit doesn’t fully support Google Analytics 4 although we do plan on further integration as more users migrate. We have more information on the plugins website with instructions on Tag Manager setup.
Do you recommend creating a new property or using the existing property?
When setting up the Analytics module within Site Kit you have the option of using either a new property or an existing property. Note that these properties are Universal (UA- prefix) Google Analytics properties, not GA4.
Any issues that I might encounter? Any Tips?
If you have already implemented Google Analytics 4 on any of your sites this won’t be recognized during Analytics module setup. You can however use a Google Analytics 4 property alongside a Universal Tracking property, you’ll find out more information on this here.
Let us know if you have any further questions on this.