I did the alps last year for the first time.
Bought an older crc bike bag off a guy on here for 20quid.
Covered the frame in pipe lagging, made spacers for the axles, stiff cardboard to line the sides of the bag along Bit more bubble wrap for good measure.
Worked well, survived sleazyjet Edinburgh to Geneva and back. No harm came to my carbon ibis.
Guy I know bought the new crc bag and it’s very close to an evoc in terms of build quality and storage.
There is a company that will hire you a evoc bag online and post it to your house.
Think evoc/silverfish are now doing the same.
Icycles in Innerleithen also have a few evoc bags that they hire out.
I’m currently debating whether it’s Morzine or Finale this year.