For the M2 Macbook Air specifically, it is currently unknown whether it is possible or not.
However, we can draw some conclusions from previous models of iPhone and Macbooks.
Such upgrades are very much possible on the M1 Macbook Air. Similar "impossible" upgrades have also been achieved on every currently supported iPhone model. There are a great many naysayers who think that board level modifications are too scary or too dangerous. People like that likely hold what is called a fixed mindset, where they don't think that things can be changed. Those with growth mindsets, believe that things can change and become better if effort is put towards making things that way. To counter their points, technicians in China have been doing it for a long time. Here are just a few links to people who have achieved such things.
https://youtu.be/0ecSzeqYX3E
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