You can visit the GitHub Build Packages workflow, click to the last successful build and scroll down to "Artifacts", and find the "Tiled-win64" artifact without ".msi" suffix. It's a ZIP file rather than an installer, so you can use it without admin.
I'd like to make it available also on itch.io, which should also work properly with the itch.io app. Only problem is that there'd be so many download options provided that it'll get rather confusing.