How to shape bandwidth fairly between processes?

While running QBitorrent, other processes get virtually no bandwidth, as QBittorrent gobbles up all of it. Chrome loads forever, pings time out etc. I could just limit QBittorrent to not use all of the bandwidth, but for that I'd have to know the maximum on the current connection, but that depends on the network I'm currently connected to which changes frequently. This is not a very elegant solution. I use Debian 9, how can I configure it to automatically shape the available bandwidth so that each process gets it's "fair" share? I understand "fair" is very vague, but what I have in mind is that if 4 processes try to download/upload at the same time, the bandwidth should be divided roughly equally between them.