This not just simple noise removal but combining multiple photos with the noise appearing in different places (aside from the hot pixels). So, it's a strategy to get much of the same effects of a really long eposure with much less noise than you'd expect based on the tiny sensor because it averages out over multiple shots. In principle of course possible to do with a DSLR as well. E.g. Hugin might be able to do this.

Of course regular noise cancellation and other very lossy processing still kicks in after that (which may explain the blurry result). It would be interesting to look at the raw image produced by this.

I use open camera on my cheap Nokia 7 plus (which uses two cameras) and have been getting OK-ish results in Darktable. The dng file you get combines information from both sensors. One of them is black and white so these look really flat until you fix it in post processing. The raw photos have lots of noise (as you would expect) but noise filtering is pretty effective.

I imagine for this it would produce a dng with information from the different stills combined but none of the other post processing (except maybe hot pixel removal).