Ironically, a properly sealed EV system would better deal with a flood. Combustion engines have issues due mostly to the air intake and exhaust.
Are EVs typically "sealed" by default? If not, how is going through the effort to "seal" an EV different than installing snorkels for ICE cars?
You'd need to ensure every electrical connection is in a waterproof location which I'm pretty sure is not a thing for any standard car manufacturing. Cabins are also rarely watertight.
AFAIK your best bet is a diesel with a snorkel, and hope things have dried off before you need to restart the engine.