Yes, the only caveat to use it as a Linux PC is that it’s using an immutable distribution.
That means that if the software you want to install exists as a flatpak then it’s great, otherwise you’ll need to tweak a little bit. You’ll have to turn your filesystem read/write and have apps installed this way be wiped at each SteamOS update.
Sorry I’m not sure I understand correctly.
30fps at 90Hz mean you’ll have the same frame twice, right? The game renders a frame, it gets displayed 3 times, it renders the next, displayed 3 times also…
How can that impact input lag? The game is only going to take your input in your account in the newly rendered frame, so every 33ms?