No mainstream alternative to Android/iOS exists. Same goes for Visa/Mastercard. All of them are US products.
Essentially shutting down all smartphones and most consumer payments would be pretty crippling.
I hope this whole thing is enough of a wake-up call for the EU to put (more) effort into a lasting solution.
Had to look it up, it's close. Wiki says the foundations were laid in 1785, so not long after the US independence.
https://en.wikipedia.org/wiki/Jaeger_Corps_(Denmark)