How to stop Photos sorting by device then date/time

You may want to check which timezone has been assigned for those photos on import, that are sorted incorrectly.

Photos is trying to infer the timezone where the photo has been taken, when it imports from the camera some photos. Photos does not necessarily read the timezone setting of the camera. It just sees the date and time of a photo, for example 9am, December 10, but not, if the timezone has been set to Tokyo or New York. If the photo is tagged with GPS, Photos will usually use the timezone of the GPS location, which may be wrong, if the camera has been set to a different timezone. If the photo does not have a GPS tag, Photos will use the timezone of the system time of your Mac, when it imports the photos. So if you import photos taken in Tokyo from your camera after returning to New York, you will get a different timezone assigned from when importing at the location where the photo has been taken.

You can see the timezone, that Photos assigned on import, when you select a photo and use the command "Image > Adjust Date&Time": You will see the timezone marked as a strip on the map, also the closest city in that time zone.

To correct the timezone, select all photos with the same, incorrect timezone offer together, then use "Image > Adjust Date&Time" to switch to the correct timezone. This will change the time displayed in the field "Adjusted". Change the time back to the same value as "Original", so only the timezone will be changed, not the displayed time.

Other than the time zone issue that Richard.Taylor mentioned different views in Photos offer different sorting options as this screenshot demonstrates:

Regarding the time zone issue, if you take a photo in one time zone and then wait to import it into your library in another time zone there will be a time differential in how the sort is accomplished. Those photos will have to have their capture time modified via the Photos ➙ Image ➙ Adjust Time & Date… menu option.

Photos doesn't care which camera took the picture. I bet what got you was time zone information. If one camera says 2:00, another might say 2:00 - 5:00. You see the 2:00 as the time, but they don't really mean the same thing. Not sure for you, but this has confused me at times.

It's a conundrum I've had to face with trips. Do I want pictures taken at the same time to appear together, or at a time that's right locally. I have photos from Wellington and London and Dallas-- but if they all say noon, some are in the dark! And if they're all pictures that I take myself, then I can't be in two places at once, so I'd rather have local times so they make sense with the photo. But if I have other family back home taking pictures, maybe I'd like their clocks to be synchronous. I think usually I like local time, but the computer makes decisions for me. Sometimes you just have to fix the time.