Valve has been amazing for linux long before the Steam Deck. They have been putting in a huge amount of work and support for Linux when they launched the ill fated Steam Machines. Back when MS was looking to force 3rd party stores out of the Windows ecosystem.
Htmx does use javascript under the hood, but just makes it so the developer can use html markdown for more a more interactive environment that’s driven sever side. So the initial page load should render, but UI elements might not work as intended.
htmx is more a move back to REST as it was originally defined (aka not json backend).