If it helps avoid the issue, you can download a .zip file rather than an installer at https://github.com/mapeditor/tiled/actions/workflows/packages.yml?query=branch%3Amaster+event%3Apush if you’re logged in to GitHub, click a recent build and scroll down to “Artifacts”.
Usually the installer is more trusted by the system though, since it is code-signed. The best solution is probably to report the installer as safe to your anti-virus solution.