Here's the new GUI of the MS20 in Cubase, set to its largest size. I can read it! And it still works with my MS20iC controller. Note - when resizing the GUI via the three dots, initially the overall frame size stays the same for me, so if making larger then some of it vanishes. To resolve this, close and reopen the GUI.

In the case of some of the other synths, its quite a feat to discover where Korg hid the resize option, often its in the screen-within-a-screen buried under a little Utility dropdown arrow. The Polysix was blacklisted by Cubase, restoring it manually seems to work ok.
Existing customers can upgrade for free, via the Korg ID Portal here - https://id.korg.com/static_pages/3 . You don't need to download the Software Pass, if you log in here you can access the new downloads.
They've also hidden the ability to buy it quite well, but found the shop eventually - https://korg.shop/software/korg-collect ... re=english . Also options here to upgrade from the old Legacy Collection to either the ARP Odyssey or Triton or both.