If you are looking for a result similar to this

You can start off with the following code:
<svg viewBox="0 0 3760 150">
<title>Timeline 2022</title>
<defs>
<linearGradient id="Gradient13" x1="0" x2="1" y1="0" y2="0">
<stop offset="0%" stop-color="black"/>
<stop offset="50%" stop-color="white"/>
<stop offset="100%" stop-color="black"/>
</linearGradient>
</defs>
<g class="bars">
<rect fill="url(#Gradient13)" x="0" y="20" width="3760" height="45"></rect>
</g>
<g class="labels" style="font-size:75px;" text-anchor="middle">
<text fill="#AAAAAA" x="{{date:DDD}}0" y="150" text-anchor="middle">{{date:YYYY-MM-DD}}</text>
</g>
<g>
<circle cx="{{date:DDD}}0" cy="44" r="30" stroke="black" stroke-width="7" fill="white" />
</g>
</svg>
This will need some work to show the dates at the beginning/end of the year as the original code was not set up to handle displaying the date in this way, but hopefully it will give you an idea of what you can do. I might be able to tweak things later this week if you need help.
You could also do something where the day of the month replaces the circle easily enough by making some tweaks to the above code. Something like this:

Although at the size of the current SVG, the value is hard to read