> Is it feasible to design an EV platform that can be upgraded to other battery chemistries?

Yes. Nio's cars can both charge and swap the battery. They can swap between 75 kWh, 100 kWh, and 150 kWh packs, all of which have the same physical dimensions. The 150 kWh pack is a new semi-solid state battery chemistry and only adds an extra 20 kilos of weight versus the 100 kWh pack:

https://carnewschina.com/2023/12/17/nio-et7-with-150-kwh-sem...