Poor performance with Nextcloud + SWAG

Hello,
I’m pretty new to this, but I’m having performance issues with Nextcloud+SWAG when running on the Raspberry Pi 4B (2GB).
I basically copy-pasted the example in the SWAG wiki (SWAG setup - LinuxServer.io), but when I try to do file transfers, I never get anything greater than 3mbps. However, when I bypass SWAG and access Nextcloud directly (by removing the overrides in config/config.php and logging in using the IP address), I get 10x the performance (~40mbps).
Is the RPI not powerful enough to handle SWAG? Or is there some configuration I could make to make it go faster?

Thanks!