Zero Trust Tunnel Throughput

I have 2 separate instances of Zero Trust. For accessing web applications it works perfectly. However I am running into problems with anything that requires throughput between client and server.
For example file transfer speeds do not exceed 4mb/s which just isn’t enough to replace a traditional VPN.

The Internet Speed from the tunnel to the internet is 250/250 so there is no limitation here. The client running WARP has a speed of about 100/20 so I would not expect to run into any problems downloading files at least.

The tunnels were configured through the portal, not CLI.
What configuration options are there to try and maximise tunnel speed? I can’t find any docs that reference this particular problem.