The team is now working on the WordPress Interactivity API. This unblocks the same UX Frontity framework enabled but directly in WordPress Core, fully compatible with the new Site Editor.
If you are using VSCode make sure you are using TS from the local repo, not the globaly installed version as it may be outdated as it was in my case.
I’m using v4.4.3 (global was 3.7.5 and was giving errors).