It asks us to download the Windows ISO from its website not from Microsoft website. So, it's a NO for me.
They are just blogging about how they used it.
Like some more reputable site also did:
https://www.xda-developers.com/tiny11-hands-on/
Maybe use that to make up your mind, in spite of the ISO not coming from MS.
Which btw. links to other alternatives like https://github.com/Raphire/Win11Debloat , which does not have the unknown ISO source problem, and a wiki explaining which does what, and how to revert it, just in case.
The post fails to mention any overview on what kinds of "debloating" the scripts are supposed to do.