Total speed is going to be bottlenecked somewhere, which could be drive read speed, upload bandwidth, or the peer's download speed, their write speed, or any number of other factors.
If your side is capable, don't worry too much about it. You could be seeding to someone on their phone in a shack in remote Mongolia. That's never going to be fast.
Also, reset all the advanced options back to default. You don't need to touch any of them, and changing things might make it worse.