Ideally yes. But with the resources needed for 25 Gbps, not using one machine for multiple purposes seems wasteful. The server only stores publically available data, though, so not a big deal from a security perspective.

What do you mean by resources required? expansion ports on the mb?

Yeah running your nas-bittorrent/firewall-router on the same OS is clearly not something I would do, especially that now you can use somrthing like proxmox for example and virtualize your pfsense/opnsense instance.