creating an ‘updated’ website offline

I made a big mistake and paid a local company too much money to screw my website up. I wanted to streamline it, reduce the amount of garbage in the code, improve the layout, and generally speed it up.The result is a site I am not happy with and a website developer that will not communicate with me. I specifically told them I did not want elementor or one of the other bloated programs and I wanted a nice simple drag and drop editor to which I could add sections. What they showed me in development is not what I got.
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So basically, I’ve decided I need to figure this out myself and it’s been a long time since I have done any of this. I figure the best way to to start is to design the site from scratch then pull the articles, pictures, database etc.. over to my offline site. Delete the existing site and upload my new one. I think this is how I need to do it in order to minimize my offline time.
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This will take me a while, as I have limited time, but I don’t have too many other options at the moment.
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what I need to know is:
1. Am I even on the right track?
2. Is an offline build still possible these days (I haven’t done much actual computer work since the 90’s)
3. What is the best sandbox to build a wordpress based site in these days?

The page I need help with: [log in to see the link]