Also experiencing this on at least two of our Elementor sites. Have tried a tonne of plugin combinations and Google Site Kit is always a common denominator. There seems to be several conflicts going on all of a sudden. Tested with Twenty Twenty theme to rule out theme interference.
1. WP back-end breaks when Google Site Kit & https://www.ads-software.com/plugins/options-page-admin-for-acf/ are both enabled
2. WP back-end breaks when Google Site Kit, Elementor (free version), Woocommerce and https://en-au.www.ads-software.com/plugins/yith-infinite-scrolling/ are all enabled
3. WP front-end breaks when Google Site Kit, Elementor (free version) and Yoast Premium are enabled together.
So there seems to be several plugins conflicting with Site Kit, making it very hard to use it right now! Have filled in the form posted above.