MacBook Pro 13" M1 has 2880-by-1800 resolution
In short, macOS uses resolution independence. This results in more than one answer for physical, rendered and logical resolution / pixel counts. If you are coming at graphics from the standpoint that every pixel is physical and there is no variance, it’s quite concerning.

https://support.apple.com/en-us/HT202471
https://support.apple.com/guide/mac-help/change-your-displays-resolution-mchl86d72b76/mac
https://en.wikipedia.org/wiki/Resolution_independence

Depending on the settings you make for scaling factor and whether an app is toggled for low resolution mode, you will see quite different “overall” resolution as well as actual and rendered resolution. The hardware and software will scale up and down components and select 1x or 2x or 3x artwork to keep items like the menu bar visible, but thin lines thin and text crisp (at least most of the time).