So, you are using multiple domains (two in my case) for your Docker Nextcloud, thats what the TRUSTED_DOMAINS is for in your config.php, but what if you want logos for each, well thanks to mediabox-cl & mepsteinj we have nextcloud-theming-domain
Installed it, navigated to the config folder on the web root of the nextcloud volume and edit the theming file.
nano /mnt/shared/nextcloud/web/config/theming.domain.config.php
<?php
# Domain Theming APP Config file (theming.domain.config.php).
$CONFIG = array(
'theming_domain' => array(
'nextcloud.example1.com' => array(
'variables' => array(
'--image-logo' => "url('/domains/example1/example1_logo.png')",
'--image-logoheader' => "url('/domains/example1/example1_small_logo.png')"
)
),
'nextcloud.example2.com' => array(
'variables' => array(
'--image-logo' => "url('/domains/example2/example2_logo.png')",
'--image-logoheader' => "url('/domains/example2/example2_small_logo.png')"
)
)
);
Happy days, each domain has its own logo.
Just wanted to make someones life a little bit easier.