Website upload speed limited. Can't figure out by what


I am facing a problem where uploading via the web interface is limited to exactly 3MB/s per client, but for example the Desktop and Android client can go up to 110MB/s, which is almost the limit of my connections upload speed.

Nextcloud is version 20
PHP(-fpm) is 7.4.11
Using Apache2
System is running Debian 10

No idea where to even start looking with this. Its not the nextcloud config, else Desktop and Client would be limited, its not the network for the same reason and its not apache, because other things I host run at 110MB/s+