I’ve installed a new game from Inkle, Heaven’s Vault.
On Windows 10 (Asus z390, RTX 2070) the mouse cursor displays in game only when something clickable is on screen BUT the cursor is frozen.
On Fedora 30 with mesa-git 19.1 (Asrock x470, 2400G) on Steam with Proton 4.2-4 there is no visible mouse cursor at all.
Moving the mouse does change the perspective in both operating systems.
Full screen or windowed, both Windows and Linux: same.
I can understand a game released a few weeks ago having problems on Linux but not on Windows.