Nowadays it's hard to tell which flagship takes the best daylight photos and the competition has moved over to the low-light photography, and this is where we can easily say which one is the clear winner.
Once again, the Galaxy S10+ takes the lead with better detail across the board. Interestingly, exposure metering and dynamic range are almost identical. If you aren't looking close enough, it's hard to tell the difference between the two but, of course, upon closer inspection, the 7 Pro's images lack the level of detail the S10+ has. We also noticed that OnePlus' flagship handles neon signs and light sources better. You can easily read signs and lamps don't look splattered. The same cannot be said about the S10+.
Switching over to the Night modes, both phones benefit from them. They both gain detail and improve the rendering of detail in shadows and highlights.
Nevertheless, the same differences from the normal photo mode apply here as well - the S10+ resolves more detail in general. Dynamic range and exposure metering are on par with the 7 Pro and the latter still makes lights and neon signs look better.
If you plan on using the Galaxy S10+'s telephoto camera during the night, you will find it very difficult. More often than not, if the software detects that there's not enough light, it will default to the main camera and crop it from there. And surprisingly enough, it will be better than 7 Pro's telephoto performance at night. Even when cropped, the S10+ resolves more detail although slightly noisier. The 7 Pro's telephoto rendition aligns with the main camera's performance and lacks fine detail.
As all wide-angle cameras, these two struggle to deliver the desired nighttime performance - scene rendition is quite poor with details getting soft and fuzzy. Yet again, the S10+'s wide-angle camera during the night is somewhat better as it delivers more detail and the dynamic range isn't as bad. The 7 Pro's nighttime wide-angle shots are just fuzzy, to say the least.
Winner: The Galaxy S10+. No matter which mode or camera you like to use, the S10+ is just better with resolving detail. In other aspects, both phones are quite comparable, but if you are looking to capture more detail in the dark, the Galaxy S10+ is the way to go.