iMessage sometimes does not sync between iPhone and Mac.

Normally my iPhone 16 and MacBook Pro work very well together, but frustratingly sometimes messages received on my iPhone do not sync to my MacBook. As I spend most of my time in front of the laptop, missing (sometimes) important messages is annoying.

If I try to sync my MacBook & iMessage, the sync completes with no new messages. I've tried the usual, logging out/back in, ensuring that I'm using the same account across devices etc. The only thing that does seem to work is from my iPhone, forcing a sync to iCloud, _then_ syncing my MacBook, after which things are fine for a short period of time. I've just done this process now (3pm) and the iPhone, despite receiving a message at 2pm claims to have not synced since 23:00 yesterday.

How long should I expect to wait between the iPhone syncing to iCloud and my MacBook picking up the message? Having to manually force a sync removes a lot of the point behind having messages in iCloud & synced across devices to begin with (assuming this is the only fix).

I've checked many other threads on this matter and tried a lot of the answers, but still, the iPhone (running iOS 18.5) does not sync in what I would consider a reasonable amount of time (if at all without a manual sync first) once it goes into this odd state.

Any answers other than the non-stock ones would be appreciated.