Error when updating from 3.5.19 to 3.6.20

[Taskerer]

Your system information

• Steam client version: 1726683985
• SteamOS version: 3.5.19
• Opted into Steam client beta?: No
• Opted into SteamOS beta?: No
• Have you checked for updates in Settings > System?: Yes

When 3.6.19 was released on the stable branch, I immediately tried to update, but when I tried to check for updates, the "Update Error" window popped up. But after I clicked on the "Back" button, a button to install the update came up, I clicked on the button, it went to install the update, but after 100%, the "Update Error" popped up again. I tried everything I found on the internet, nothing helps. Before that all updates were installed without problems. I also found 2 tracks on reddit where people are reporting the same problem and the same problem for two of my friends. So the problem is massive. Would be very happy to solve this problem without a full data reset. Also ready to provide any information or test a possible solution if it will somehow help in solving the problem.

Steps for reproducing this issue:

1. Click the "Check for updates" button
   2.The "Update error" will pop up, press the back button
2. Click the "Install" button
3. Wait for 100%, after which the "Update error" will pop up again
   

[Taskerer]

Trying to upgrade to 3.6.20, same problem