Do you have a list of peers in one of the tabs? If it's not a currently trending file sometimes you're at the mercy of who has it and is seeding, could even be just one person. Could be other things going on, but that's my first thought.

I find I regularly have to restart it or restart the networking bits by changing a network setting then restoring it.

If anything with networking gets messed up, it just stops.

My old app used to reconnect properly after a glitch, but not qBittorrent.

You might be dealing with a similar issue.

It doesn't happen often, maybe once a week, so it's not the end of the world for me, but it sucks.

I'm pretty sure my qb problem stems from the vpn connection. When my torrents stall I quickly restart gluetun and qb and that fixes my problem and the downloads resume