With Lufthansa ... Light/Classic/Flex do not "map" to specific fare buckets.
Think of these more as "bundles." But the "bundle" can be any fare class.
When booking on LH.Com or Eurowings.com -- in each "bundle" they offer ONLY the cheapest existing fare. You can't select a higher fare for any of the "bundles."
I think Eurowings works the same way since it's basically run on LH structures.

So for example, I recently bought the most expensive, Flex, fare ... but it turned out to be a "K" fare which earns no miles.

Or another time, selecting a Business fare, the only business fare it gave me was the cheapest fare ... a NONREFUNDABLE, NONCHANGEABLE fare (P). I could not buy a more expensive, flexible business fare!

And you don't know which fare class until after ticketing. So it's kind of Russian Roulette here. You can buy it, and then use the 24 hour cancellation if it's the "wrong" fare. And then wait for the flight to start selling out and when the cheaper fares are sold out, then you got the one you want.

Or you can call and pay the extra 20 euro to get the ticket issued by the call center, and they can do it in any available fare class.

Or you can try booking on expedia or other ... the fares may be higher, but at least they will let you know the fare class before you ticket!