OpenTofu not supported even though Readme says to use it

[tuffacton]

When attempting to run OpenTofu tofu commands I get registry retrieval errors like so, but not with terraform:

│ Error: Error accessing remote module registry
│ 
│ Failed to retrieve a download URL for registry.opentofu.org/terraform-aws-modules/vpc/aws 5.19.0 from registry.opentofu.org: failed to get download URL for
│ "registry.opentofu.org/terraform-aws-modules/vpc/aws": 200 OK resp:{
│   "location": "git::https://github.com/terraform-aws-modules/terraform-aws-vpc?ref=v5.19.0"
│ }