the file size limit seems to be 2 GB. The latter page also explains how to set the sizeLimit attribute (was able to upload upto 10GB from browser by increasing the sizeLimit) (/libs/dam/gui/content/assets/jcr:content/actions/secondary/create/items/fileupload),
the 2GB limit is imposed by the browser. Additionally In order to add a larger file, it can be done through AEM Desktop also
Technically there is no limit & able to configure the limit. SHould not be performance issue & make sure enough disk space available. However the client reading the assets might have an limitation & cause performance issue.