@Dominik_WR
Yes, your problem seems to be exactly the same that I had. I did test it pretty thoroughly and the problem was the combination of Ubuntu 18.04 or 20.04 with NTFS-filesystem. Ubuntu 16.04 was working fine also with NTFS.
I have used VMware since then on ext4-filesystem and it works just fine on Ubuntu/Kubuntu/Ubuntu Studio latest LTS versions (20.04.x) . SSD, HDD and external SDD-USB3 - disks are all giving the expected performance (for a VMware computer) when there is ext4 filesystem in play.
