Standalone: Timezone improvements
It doesn't look like standalone has a setting for a site-wide default timezone. It means anywhere where anonymous sees timestamp fields (as opposed to datetime fields) they'll see whatever the server default is, but without a way for the average site admin to "fix" it. At the moment I'm drawing a blank as to which screens this would be. Something like a creation date, or an activity date if you have doctorwhen installed.
I also don't see where php's timezone gets set, which is somewhat equivalent to a site-wide default. There might be some places where that will come up, but am also drawing a blank on where at the moment. Drupal sets it in drupal somewhere, and see e.g. what wordpress does for civi: https://github.com/civicrm/civicrm-core/blob/888e65374f208e6d79ff8adc68d0adfa05575277/CRM/Utils/System/WordPress.php#L732