As soon as I found out the RAID controller, I was resigned to reinstall windows. However, I used the procedure #2 in
https://askubuntu.com/questions/963087/install-dual-boot-ubuntu-with-windows-10-and-raid-on
And could change from RAID to AHCI. Everything is working now. It would be nice to have this procedure documented in the CL installation docs.
I must say, the first boot on CL felt like a breeze in the desert.