Well... it's not so much the physical size as it is the pixel size itself. The V30's 16MP sensor is is 5.87mm diagonally with a 1.0
μm pixel size. To put that in perspective, the first generation Pixel's 12MP sensor is 7.87mm with 1.55 μm pixels. The new Pixel uses a different sensor, a 12MP that runs 6.84mm (1.4μm)
Yes, they have a wide aperture and top quality glass lenses, but they NEED a wide aperture and top quality lenses to compensate for those wee pixels.
All things being equal, smaller pixels are more prone to noise than larger ones... and that increased noise sensitivity becomes even more an issue as ISO values go up.... which then requires more noise reduction processing... etc. And whether this is intentional or not, LG tends to go way overboard with NR and they end up stomping on real data in the picture.
I have a couple of samples kicking around here somewhere where I took some shots of a calendar that I had hanging on the wall of my office. With the 6P I have (sensor was same size as the Pixel 1), if you looked at the calendar you could see the slight variations and grain of the paper it is printed on. Same shot with my G6, paper looks like solid white.
Now, here's the thing... those shots from the G6 have less noise than even the Pixel XL I just picked up. But contrary to what's been hammered into our brains... noise isn't necessarily bad and sometimes it adds a bit of character to a picture. So while my XL might have more noise, it also retains a significant amount more detail along with that noise. To be honest, the 6P/Pixel's shots have a film-like quality to them.... They might be softer and have more noise, but they look REAL.... like an actual photograph. The stuff I get out of my G6 has been processed so heavily that it ceases to look like a photograph and instead looks like a digital reconstruction. (Yes, I know Google has HDR+ which is, by a WIDE margin the best image processing in all of mobiledom, but it is what it is)
OK... I just went way off the rails here... but I could talk about this stuff all day.
Long story short... LG did themselves a great disservice by not going with larger camera sensors. Because staying small means they have to rely on their processing more, and their processing sucks sewage.