[SwissXC90]

The cheapest and best long- term solution is to replace with 2nd hand headlamps of the same type.

I say headlamps, as you need to replace the entire headlamp unit.

Not all go cloudy. My 12 year old lenses are still crystal clear - but then my car has been garaged all it's life.

It's primarily UV radiation from the sun that makes them go cloudy.
So if you hunt, you might find 2nd hand headlamps that are clear

Changing from Xenon to Halogen will not work due to wiring and programming of the car. Best not to go down that path. Dealer cannot recode, as change of headlamp types is not codable option.