

This is what I do, I enable HDR on:
- My Monitor’s menu (hardware)
- Steam Game Mode
- KDE Plasma monitor config (software)
- Game settings
My monitor isn’t OLED, so the difference is barely noticeable to me. Even on my Steam Deck OLED, the difference is not big enough for me. It’s nice, but I just can’t appreciate it as much as others do. However, I do graphic design so the color management aspect is more valuable to me in a work context, just not so much for games.
If you want a set it and forget it distro to never touch his computer again, then consider going a Ublue distro. Aurora (only KDE), or Bazzite (choose the KDE image) if he does gaming.