@carnoxen You can create both a Universal Analytics (UA) or a Google Analytics 4 (GA4) property from analytics.google.com at present, or you can use Site Kit to create one of both if you wish.
When it comes to connecting a property, Site Kit will connect your site with both. You may choose not to allow Site Kit to place your UA or GA4 snippets if you choose, but the plugin will remain connected to both.
If you’re referring to displaying GA4 data within the Site Kit dashboard, as opposed to displaying UA data, this is being worked on. Soon the Site Kit dashboard will be able to display data based on the connected GA4 property. You can keep track of progress on this over on the plugins GitHub repository.
Let me know if you have any further questions on this.