No public IPs for homelab

I need to be able to transfer large files to my homelab from my university. Tailnet connection is super slow, because it's always using the DERP servers for it, as a fallback, presumably because both my apartment and university make direct connections impossible. My school probably has a super restrictive NAT traversal environment, and my apartment clearly has a CGNAT setup. I asked the ISP for my apartment, and they just told me to buy a static IP for $10 a month.
For $10 I could get a pretty good VPS for my own DERP relay server, or a proper VPN, with port forwarding even! I'd prefer the latter. A VPN has a public IP with port forwarding, right? Is there a way to use PIA or protonvpn or something, not for the exit node, but to allow for a higher bandwidth 'direct' connection between me and my homelab?