There's not a lot of information in your ticket to go by so I'll have to make assumptions based on the merger information you provided.
First of all, I make an assumption that your backup is from immediately before or temporally rather close to the installation of the broken extension update and the subsequent site restoration. If your backup is from much earlier and taken with a different version family of Joomla please tell me so and stop reading any further.
The only thing which would simultaneously cause all three problems and have something to do with the restoration is that you entered a Live Site URL in the Site Setup page during the restoration, but added a space at its end. This means that your configuration.php has a line such as:
public $live_site = 'https://www.example.com ';
Note the space before the closing
';. Joomla will use that as-is, errant space and all.
Please edit your configuration.php and change that line to
public $live_site = '';
Do keep in mind that you do not need $live_site on practically any server anymore. This is only required on some mostly broken setups where a proxy / load balancer in front of the web server does not pass the HTTP Host header to the web server, therefore Joomla cannot determine which hostname to use. It's extremely rare but can conceivably happen which is why this feature still exists in Joomla.
Nicholas K. Dionysopoulos
Lead Developer and Director
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