«Download Folder» fails creating/streaming zip-files above 500mb

Operating system: Linux 3.10.0-962.3.2.lve1.5.35.el7.x86_64
Webserver: LiteSpeed (litespeed)
Database: mysql 5.7.26
PHP version: 7.4.10
Nextcloud version: 19.0.4 -

When we download a folder that is bigger than 500mb, the streamed zip-file is corrupt. Our hosting provider told us, that the zip-files are created and saved in the servers RAM. The (for us unchangeable) configuration halts that process at 500mb - and returns a success statement (therefore no trace of error in nextcloud logs).

I guess this happens with the ZipStreamer in Streamer.php.

Is there any way to have those zip-files created in the filesystem (in a temp folder eg.)?
If not: can I disable this feature anywhere?

thx for your help!

cheers and best regards