> there has to be a physical switch

Or literally any $1-3 SPDT RF switch? >80% of which are directly optimized and advertised for wifi and bluetooth?

For a Zero, that’s a big BoM item given this would be used by relatively few people.

Yeah, western parts are expensive.

https://www.lcsc.com/product-detail/C47117600.html

Here's a capable switch for $0.07.