First real-world gaming test: NVIDIA RTX 5080, Cyberpunk 2077, Satisfactory. Spoiler: it works, but the first run-through has its rites.
Steam and Cyberpunk 2077: the smoothing
I install Steam from Zorin's Software app. No problem.
Then Cyberpunk 2077 from Steam. Also no problem: download and decompression go fine.
I launch the game — and it's a disaster: less than one frame per second.
Diagnosis: the OS is using Nouveau, the open-source driver for NVIDIA cards. Fine for a desktop, useless for a AAA.
The proprietary NVIDIA 580 driver: the dance
Off to Software & Updates, Additional Drivers tab. I pick the proprietary NVIDIA 580 driver. Reboot.
On reboot: driver not loaded. Reason: I still have Windows in dual-boot, so Secure Boot is on. Detour through the BIOS to allow unsigned operations on Secure Boot (on the Linux side, this is the MOK enrollment ritual).
Reboot: NVIDIA loads, but so does Nouveau. Not great — need to blacklist Nouveau (a blacklist.conf file in /etc/modprobe.d/ that disables the module).
Reboot. Cyberpunk 2077 test: same graphics quality, same FPS as on Windows. ✓
Satisfactory via Epic… via Heroic
Second game, different launcher: Satisfactory, which I own on the Epic Games Store.
Except the Epic Games Launcher doesn't exist on Linux. The workaround: Heroic Games Launcher, a third-party client that drives Epic, GOG and Amazon under one UI.
Install Heroic, log in to my Epic account, download Satisfactory. Launch. Works perfectly.
Worth noting
Both games are the Windows version. Proton is what translates the Windows calls to Linux in real time — used by Steam, and by Heroic too. At no point did I have to hunt for a "Linux version" of a game: the Windows version is enough.
Provisional verdict
The thing I worried about most before switching — games — turns out to be the least of my problems. A few extra steps the first time (proprietary driver, Secure Boot, Nouveau blacklist), and after that it's just click and play. As smooth as Windows.