It's probably limited by your internet service provider. On many plans you only get much less upload speed than download speed. I guess it's to discourage home users from running a server at home. And to discourage file sharing.
Yeah that's probable. Since changing some settings on the connections limits it has already increased, still not as much as peak download like you said.
Connection limits could be one part of the story, im not sure what the defaults are in qBit but i have set mine at 100 or something like that. Another issue that you could be facing is the torrent itself, it might already have 100+ people with seedboxes seeding but only a few peers downloading, since so many people are alredy uploading its hard for you to get any upload in. Try a few other torrents, preferably once with only a few seeds but quite a lot more people trying to download.
Don’t worry about the speed. The important thing is that you are giving back. Seed to at least 150% or forever if you can. Your upload speed is usually lower than your download speed from your isp.
I run 4 vms that are seedboxes. Each are on vpns and I've observed them to hit up to ~90MBps, just shy of gigabit (I have 8gbps). Most of the time I'm not uploading much at all. It's not just you bandwidth and the VPN that matter. But also the peers that's making the request. Sometimes they just don't talk to you but the other peers. Or they don't have that much download bandwidth. The only real way to test is to self host your own torrent and grab it from a controlled outside peer. See what it actually gets when you pull directly.