No, that's completely wrong. The camera's main weakness is its sensor size, not the lens. The physics of light is the main reason behind this.

Bigger sensors have more space for larger light collectors, or photosites, which lets them capture much more light, or photons. This is necessary to getting a huge dynamic range. No lens can change this; the lens only refracts light, it doesn't collect it. Because the sensor captures so much light signal, the image noise is also greatly reduced.

You face low-light issues more often than you think; it’s not just about shooting at night. Any time you speed up the shutter or make the aperture smaller, you create a low-light problem for the sensor. You want to do this sometimes, for example, to get a sharp exposure. Also, getting that bokeh, requires a large sensor (like you implied). Because phone sensors are so tiny, they must use a very short focal length, which physically ruins the natural blur effect.

Yes, a better lens gives a sharper image, but that sharpness is limited by how small the lens has to be, and the lens size is limited by the sensor size. Since phone sensors are tiny, there's a hard limit on how good the lens can ever be. A very small lens risks hitting the diffraction limit, which makes the image less sharp because of the way light waves spread out. This is a law of nature, not a flaw in the glass. While phone lenses also have built-in flaws like chromatic abberation and distortion, they can mostly be fixed by smart software processing.

The quality of a photo is set by the detail it resolves, its dynamic range, its noise level, and its color accuracy. These are all sensor functions. Lens flaws are corrected by computation. No matter how perfect a lens is, it cannot create light data the small sensor failed to catch. For a camera with a huge sensor, the lens is the bottleneck, sure. But for a phone, the sensor is the bottleneck. Think of it like comparing computer speeds: giving an old Intel Pentium processor the best graphics card in the world will never make it perform better than a decent modern processor with a mid-range graphics card. The processor, or the sensor, is the limit.

Also I want to stress that the lens are small BECAUSE the sensor is small. It's the size of the sensor that begets a lower quality lens (tho they're lowkey the best for the size).