ISSUE

Checked on Steam Deck in Desktop Mode.

In Steam Settings -> Interface: Timezone... the setting is set to 'Pacific Standard Time' (which is not correct) and is not reflected in the System time. Changing the timezone will also not save. When changing the timezone, clicking to another setting screen, and then clicking back to Interface, the Timezone is back to 'Pacific Standard Time'- no other Timezone will save.

OS
SteamOS 3.6.20

STEPS
In Steam Deck, Desktop Mode, Select Steam > Settings
Go to the section called Interface
Change the the Timezone to any zone EXCEPT 'Pacific Standard Time'
Navigate to another section in Settings or completely close the Settings window
Return back to Steam > Settings and view the Timezone

RESULTS
The Timezone selection is back to 'Pacific Standard Time'.

EXPECTED
The Timezone selection should have been saved to whichever Timezone was previously selected.