Hello,
I'm facing the issue of not working sync of Safari tabs across my devices.
I'm currently on macOS 15.2 Public Beta and iOS 18.2 Public Beta and sync still doesn't work.
When I try to turn it off on all devices and set-up again it starts working and sync properly but only one time, than again stop working properly.
It's also described here as an issue: https://discussions.apple.com/thread/255767048?sortBy=rank