Free Windows 10 support ended for most people this past month, and the trend line of Linux usage has been quite clear leading up to this, as people prepared for the inevitable. An increase in Linux usage is also correlated to a drop in Chinese players, which did happen this month a little bit, but Linux usage is also trending up when filtering for English only. It's worth noting that for all the official support Macs ever saw in gaming, they never represented anything better than about 5% of the market.
THPS offline mode is the same version as elsewhere, but it magically allows itself to operate offline when it thinks it's running on a Steam Deck, which you can do with a launch parameter. Baldur's Gate 3 actually has a native Linux version that is only officially supported for Steam Deck, and that might be closer to what you're referring to.