A relative was using MS Paint to draw some simple floor plan diagrams and asked whether there's any better tool available.
Gimp is actually overfeatured for what they need, but that was the only thing I found which I could install with a good enough certainty that I won't infect their computer with malware.
I strongly advise against Paint.NET. Besides the lack of download security they have huge "download" ads leading who knows where on the front page and a tiny download link.
They are knowingly using this dark pattern to make ad money which is too bad, because as you say the app is really good.
Gimp is actually overfeatured for what they need, but that was the only thing I found which I could install with a good enough certainty that I won't infect their computer with malware.