AFAIK whether page will be restored or reloaded depends on its cache headers. I remember breaking back button in one of my projects, because users asked for it, as they expected fresh data for some reason. It was not SPA, just old server rendered website, so I disabled caching via response headers and it worked.
I found no setting. Im using an addon "ModHeader" to set the response header (for all websites) "Expires" to a date far in the future. It worked in the past, but doesn't work at the moment. Have to debug it.
Edit: Also I'm not sure that is the relevant one? Reddit sets Cache-Control to "private, max-age=3600 [seconds]", but it definitely reloads the content if I back up in less than an hour.
