Iphone 11 Pro Max will not sync with MAC and this has been going on now for 2 years since IOS Catalina

I can not get the iPhone 11 Pro Max to sync with MAC. This is critical as I have a large volume of photographs due to the work that I do as an artist and need to keep my photos on one main system (MAC) with an iCloud backup. Since the launch of Catalina in Sept 2019 I can not get the iPhone 11 Pro Max to sync on a consistent basis with the MAC. I have to turn off / reboot / enable-disable IOS device / Check USB cords. This should be a simple task and it was until Catalina. The idea of having all photos in the iCloud and to use as and when needed is a nice concept unless you have 40000+ photos and there is a presumption that one is always in network to access / download. This MUST be resolved. It has gone on too long. Why have the ability to sync the iPhone in Finder? That was the biggest joke because before when one disconnected the phone there would be a request to disconnect. Now you just pull the plug out and frankly I do not think that Finder then knows to look there after you unplug it (only once you successfully connect with happens only one in a blue moon). PLEASE PLEASE RESOLVE!