Browsing history not syncing across all devices?

Hello, I’m having an issue with iCloud history on Safari not syncing on both my iPad and iPhone. Originally the history wouldn’t show on my iPad if I searched on my iPhone but would show the other way round.

To try and resolve the issue I cleared history and data for Safari, restarted both devices and turned off and back on ‘share across devices’ and now none of them sync.

Is this just a minor inconvenience and should I not worry? Any other quick suggestions?