Steam doesn't launch after flatpack install

[june012006]

Kasm 1.17
kasmweb/steam:1.17.0-rolling-weekly
GPU was configured per kasm documentation
GPU NVIDIA GeForce GTX 1070
CUDA Version 12.8
NVIDIA Driver 570.124.06
Agent shows GPU in "Usage" tab, but only reflects a miniscule (0.31%) memory usage, and GPU temp of 50C
persistent profile is enabled

Upon first load, or after persistent profile is reset/disabled steam flatpack install runs, followed by the steam configuration progress bar. After that completes, all I see is the kasm desktop wallpaper. If it is the second time running, with persistence, it just shows the desktop wallpaper. There are no menus, only the background and the cursor.

[june012006]

In ~/.steam/steam/logs/webhelper.txt I see the following repeated through the file.

[2025-07-06 08:12:03] SharedJSContext-'SharedJSCo': WARNING: https://steamloopback.host/library.js:2: failed to reach open state
[2025-07-06 08:12:03] SharedJSContext-'SharedJSCo': WARNING: https://steamloopback.host/library.js:2: connect attempt failed: 2 - failed to 
reach open state

and this is in the transport_steamui.txt file within the same path

[2025-07-06 08:54:37] WebUITransport: Connection from: 127.0.0.1:45472
[2025-07-06 08:54:37] WebUITransport: Checked: 0/2050
[2025-07-06 08:54:37] WebUITransport: Connection rejected
[2025-07-06 09:05:43] Warning: SteamUI thread frame stalled for: 666038 ms


[2025-07-06 09:08:46] Client version: 1751405894
[2025-07-06 09:08:46] WebUITransportController: Initialized
[2025-07-06 09:08:49] WebUITransport: Websocket connection from: https://steamloopback.host
[2025-07-06 09:08:49] WebUITransport: Connection from: 127.0.0.1:41422

The last time I had the session running, it did eventually give me a 0x3001 error, which is why I thought to look at these logs.