To get the convertions to DotVVM done you need to learn how the ViewModel concept works. I mean this is the same hurdle you need to overcome if you want to rewrite your project into Blazor, which I refused of doing because there is DotVVM which I like better.
Anyway I checked the documentation, the YouTube videos but I didn’t find anything on how to simply convert this to DotVVM:
protected void Page_Load(object sender, EventArgs e)
// do something
Handling Buttons convertions you are showing in the videos. But not the initial on load page.
Maybe this is something for the cheat sheet or the missing “Plan of modernization”