I haven't used it (I prefer to write my site myself), but perhaps https://bearblog.dev/?

Nice, that does fit the bill!

Note that it does not include custom domains or image uploading on the free plan, but you can upgrade for $29 (lifetime), which gets you:

    Custom domains (this is time-consuming)
    Image uploading (due to the cost of hosting images)
    Email subscriber lists (since it gets complicated)
    Beta features (since they aren't ready yet)
    You can upgrade for $29, flat.

The editing interface is just a textbox where you paste markdown; doesn't seem there's a github integration or anything like that, which is too bad.