Feedback on the Lenovo ThinkCentre M75t Gen2 (202009-28208)

I tried to install Ubuntu 20.04 on my new Thincentre M175t Gen2 besides Windows 10 (64 bit). For Ubuntu I am using a SATA SSD.
Live System from the installation USB stick does work.
I tried to use the EFI partition of the Windows system and also to use a EFI partition on the SATA SSD, both with the same (negative) result:
When booting after installation the GRUB 2 menue is displayed. Selecting Ubuntu the system doesn't start up, only displaying a black screen.
Seems not to be a problem of the Linux distribution, since I also don't get a Linux MX 64bit running.
I also disabled the secure boot option of the UEFI, but this didn't help.
Also I tried with and without loading third party drivers during installation - no difference.