If you look at the various options being suggested in the comments here you'll see many of them don't come with comments out of the box. Jekyll, Gatsby, Hugo, 11ty all require you to use a third party service or roll your own.
Yes none of those static site generators support commenting, making them not very suitable for blogging(they dont even support searches). That is why I am not a proponent of static generators as a blogging platform.
Like the GP, I was also under the impression that Ghost doesn't support commenting by design but you are suggesting otherwise. I find it hard to believe that adding commenting system(something that all major CMSs have had since forever) would be that technically challenging that it hasn't been added even six years after its first release.
This is assuming you are willing to pay for at least your own server. Their hosted option is also great and highly recommended if you want to just start writing before thinking of customizations.
I find static site generators to be awesome but generally a hindrance to the flow of wanting to start writing spontaneously. More often than not, more time goes into figuring out the perfect workflow for the blog system rather than writing. Caveats, YMMV etc apply :)