This doesn’t necessarily have to be the problem.

The lens must be large enough against the sensor to allow enough light to pass through, and the small sensor only needs a small lens. What you then see with DSLRs, for example, is that you see those huge bells, and that has to do with the fact that they have zoom, and the higher the zoom, the larger the aperture of the front of the lens has to be to allow enough light to pass through. to leave.

Take this one for example lens, aperture from 3.5 to 6.3, this means that when zoomed out, you can shoot at 3.5, and zoom in at 6.3. This number affects the amount of light entering and the amount of focus. The smaller number is more light, but less concentrated. Of course you can always make the aperture larger, but you can never make the aperture larger than the lens physically allows.
This is also a lens that performs up to 16x magnification. (18-300 – this is what we see as 1x magnification for 16x magnification)

Here you have one 120-300Here you see the forehead is wider and it also doesn’t have 3x magnification this has to do with the fact that if you want more magnification you need more and more lenses and that takes up space and the longer the tube the bigger it has to be towards the front to get on adequate lighting. This is a lens with aperture of 2.8 and 2.8 that is pretty much the size that professionals use as “normal” lenses, and it’s about 3 times the magnification (24-70, 70-200 etc.)

In the case of the phone, you’re talking about a prime lens, because there’s no zoom (digital zoom doesn’t count), so the prime lens has one fixed size, and that makes it more difficult to use, but you can too. They easily let in a lot of light, because these lenses are very intense small After all, it should have much less glass, and because it is so close to the sensor, you quickly have a lot of light. These types of lenses are handy with an aperture of 1.8, but you also have an aperture of 1.2 (I don’t know how small it is). With such a lens, you can let in a lot of light, and you can focus on a very small part, which can give very impressive effects. Less lenses also have some other advantages.

For example, the 108MP camera on the Galaxy S22 Ultra has an f1.8 aperture, but the largest zoom has an f4.9 aperture.
If the glass is good, this wouldn’t be a problem as far as I know.