A bit of insight:
iCloud: Dissapointingly the upload speed is slooooow regardless of whether I use Ethernet or WiFi. I think Apple are throttling the upload speed which is understandable given that there are hundreds of millions of Apple devices syncing with iCloud every hour.
Therefore when I want to quickly offload videos from iPhone, I use my Samsung T6 and edit directly off it on my MBP. Even rendering files are stored on it and the experience matches the internal drive.
Google Drive: Upload speed seem largely unrestricted. A 7GB file uploads as quickly as you can go to the toilet for a wee and then fill a glass with water. 160-180GB batch of video took me 45min to upload. It’s genuinely fast and I recommend it over iTunes if you urgently need to free up space on your phone in order.
Other than that there is no discernible difference in Ethernet performance between my iPhone 15 Pro and M1 MacBook Pro.