The restore timeout issue is usually related to the server limits, you can try to change the following settings:
In WPvivid Advanced Settings:
- Change PHP script execution timeout for restore to 3600 seconds(try 7200s or higher if the backup is large in size)
- Change PHP Memory Limit for restore to 512 MB
- Save changes
Also, check if the site is on a Litespeed server, as on a Litespeed server, in order to optimize the network, it will kill requests that exceed a certain time, for example, 30s.
So you can add the following rules to the .htaccess file to prevent Litespeed timeout.
<IfModule Litespeed>
RewriteEngine On
RewriteRule .*-[E=noabort:1, E=noconntimeout:1]
</IfModule>
Please do not refresh or close the restore page until a success or failed message appear, as the restoration is actually still running in the background until that.