After Update to 14.0.4 problems with overwrite.cli.url and subdomain

Hello together!

After upgrading my Nextcloud to 14.0.4 today, i face a strange error.

Nextcloud version: 14.0.4
Operating system and version: Synology DS918+ DSM 6.2.1-23824 Update 1
Apache or nginx version: Apache 2.4
PHP version: 7.0

My Nextcloud is in the folder /web/nextcloud which is accessible via a vHost under cloud.domain.tld

According to that, my config.php hat the two lines
'htaccess.RewriteBase' => '/',
'overwrite.cli.url' => '/',

After the update (which wasn’t successful via the web updater, had to delete all files and move the new files into the directory) i can’t access my Nextcloud anymore. When i enter cloud.domain.tld, I’m getting redirected to domain.tld/nextcloud. I don’t understand why, since I didn’t change anything. But beside from that, which might be a problem of my server, i have the problem, that i can’t change anything in my config.php concerning the overwrite.cli.url:
If I enter ‘overwrite.cli.url’ => ‘/’, and run a /occ maintenance:update:htaccess, i get the error
Error updating .htaccess file, not enough permissions or "overwrite.cli.url" set to an invalid URL?

Which kinda confuses me, because that was the given value before the update.
Actually, the only thing which works right now as value, is
Anything else, even
results in the same error message.

Is there anything changed in 14.0.4 which could lead to that problems?

Sorry if my problem is kinda confusing, I’m more or less confused by myself. If any part needs to be explained more detailed, please let me know.

/edit: I just realised, I can access e.g. shared links via cloud.domain.tld/s/ABC123
But as soon as I enter cloud.domain.tld, I get redirected to my domain.tld/nextcloud path.

‘overwrite.cli.url’ should have the full URL.