TCLI gives you a URL after successfully uploading but this link doesn't include the community subdomain. Uploading to the 'test' community on thunderstore.dev gave me this:
https://thunderstore.dev/package/download/northstar/NorthstarLauncher/1.5.1/
instead of:
https://test.thunderstore.dev/package/download/northstar/NorthstarLauncher/1.5.1/
Terminal output:

Using tcli 0.1.4