Pixel X = Flagship, most expensive with best hardware and most features
Pixel Xa = Cheaper version of Pixel X, often with one tier down processor, less RAM, and lacking some features like wireless charging
Pixel 4a 5G (marketed as a 4a with 5G support) is somewhat of a weird case where it's actually closer to what we'd expect from a Pixel 5a (which is likely why it was discontinued while the Pixel 4a was not)
The 4a 5G and 5a are separate phones, but target roughly the same price point and feature set (basically the mid tier "phone with 5G" market). When the 4a 5G launched years ago the 5a didn't exist. Now that it does the 4a 5G is being discontinued.
Yeah, the naming scheme sucks, google should have just called them the 5a and 5b or something.
Usually, the Pixel Xa is a newer, more budget-oriented version of the Pixel X. "5G" variants of phones seem to be totally different phones, not just a radio upgrade.
Pixel Xa = Cheaper version of Pixel X, often with one tier down processor, less RAM, and lacking some features like wireless charging
Pixel 4a 5G (marketed as a 4a with 5G support) is somewhat of a weird case where it's actually closer to what we'd expect from a Pixel 5a (which is likely why it was discontinued while the Pixel 4a was not)