DB issue "SQLSTATE[HY000] [1040] Too many connections" using "Upload the whole camera roll" function on iPhone

Hi all,

I am using the nextcloud 20.4 as docker-compose from the docker page and on the iPhone the nextcloud app 3.10 version.

I am trying to backup all photos/videos on the device to my server. Unfortunately I run into the issue

An unhandled exception has been thrown:
Doctrine\DBAL\DBALException: Failed to connect to the database: An exception occurred in driver: SQLSTATE[HY000] [1040] Too many connections in /var/www/html/lib/private/DB/Connection.php:72
Stack trace:

I am trying to upload >50.000 photos/videos, which is of course a lot. Nevertheless, from my point of view this should crash the nextcloud, which it does. I have checked the internet and there are information, that the mysql standard max_used_connections is 151, which is also in my case.
My question is, is this an issue with my configuration, or does the app needs to handle these amounts different?
Another user seems to have a similar issues with ~9.000 photos/videos.

I hope you can help me with some feedback and maybe even a solution.