Quick answer: After the Nov 4 patch (1.0302256), SteamDeckHQ retested Phantom Blade Zero: on Steam Machine at 2K, Medium and FSR Balanced it now holds nearly stable ~60 FPS in former problem areas, while Steam Deck still cannot hold a stable 30 FPS even on lowest settings.
SteamDeckHQ retested Phantom Blade Zero after S-GAME's November 4 PC patch (version 1.0302256) and says the Steam Machine experience is much better, while the Steam Deck remains a skip. The official patch notes list improved performance in certain areas, faster shader compilation on PC, combat and audio tweaks, Bluetooth controller stutter reductions, NVIDIA Reflex fixes with V-Sync Auto, and assorted bug fixes.
On Steam Machine, SteamDeckHQ used the same settings it recommended before: 2K resolution, Medium quality and FSR Balanced. Areas that previously forced a 30 FPS lock for a stable run now hold nearly stable 60 FPS. Fights that used to drop hard stay close to 60, with minor dips around 57 FPS and a low of about 51. Crowded spots like Pangzhen stay above 50 FPS with only small stutters. SteamDeckHQ now recommends the game on the Machine.
On Steam Deck, the same patch does not unlock a stable 30 FPS even at the lowest settings. Crowded areas and larger fights still stutter and can drop around 20 FPS. SteamDeckHQ still advises avoiding the game on Deck for now and hopes for more optimization later. That follows its earlier review, which scored the game highly as a title but unplayable on Deck before this update.
Tested on the channel: Phantom Blade Zero on the Steam Machine: Performance Test (video) · full article