is it possible to configure it to download faster on my Qnap node?
Do you use the Uplink for managing buckets, store and retrieve objects?
Or have you installed the app for Storage Node Operators to offer a free space to the network?
I don’t know anything about the link, I just read that its correct configuration can speed up my Storj node
The upload and download performed by customers’, no one option in the config can force them to use your node more often than others.
If you do not use network connected storage like iSCSI/NFS/SMB or SMR disks there is nothing you can improve.