iPhone 17 Pro Max unable to send photos that have just been taken with the camera.

I don't use iCloud Photo but it seems that it's waiting to upload your recent photos to iCloud before you can send it. The fact that you can send older photos seems to confirm that in that they had time to upload to the iCloud Photo library.

Do you have Optimize Storage activated on your iPhone?

I tried to replicate your experience on my own 17 Pro Max connected to iCloud Photos, but was unable to do so. New photos could be sent by iMessage immediately. However, my phone was not having sync problems at the time.

If you are still having sync problems, you should try to troubleshoot those first. Do you get any additional text explaining why your sync is paused (maybe saving battery or keeping the phone cool)?

I would also be interested to know the answer to Old Toad's question about whether you use the Optimize iPhone Storage option on your device. I do not have it active on mine.

Why hasn't anybody replied with a fix? Is this just bugged forever?