Best Dreamweaver workflow for building a large website with online calculators?

As ​@Nancy OShea mentioned, if this is a plain static site with hundreds of separate calculator pages, maintenance can quickly become a real problem.

That said, I think there is another point worth mentioning. The question is very broad, but the site shown does not look like a simple hand-built Dreamweaver site made by someone just discovering templates, reusable parts and Git.

Looking at the front-end code, there is already a fairly organized modern structure: SEO metadata, Open Graph tags, JSON-LD structured data, Google Tag Manager, theme handling, responsive navigation, language selector, organized class naming, shared CSS, and commented sections. The code also uses things like data attributes and encoded multilingual labels, for example in the language selector.

So there is a bit of a mismatch between the question and the apparent level of the existing code.

Of course, that does not prove who built the site or how it was produced. It may have been generated, built from a template, produced with another tool, or assembled by someone else. But it makes the Dreamweaver part of the question difficult to evaluate.

Without a specific Dreamweaver issue, a specific page problem, or a concrete workflow failure, it is hard to give more than general advice.

At this point, the post reads more like a general mention of a website than a specific Dreamweaver support question. It also raises the possibility that the question is mainly being used to draw attention to the linked site, rather than to seek help with a clearly defined problem.

I see no evidence of server-side code so I’m guessing this is a plain static site. A static site containing hundreds of separate web pages will soon be a 10,000 lb. gorilla, if it’s not already.  

For comparison a similar site, OnlineConvert.com, is built with WordPress (PHP 8/MySQL database) and these web technologies: 

https://w3techs.com/sites/info/online-convert.com

Content is stored in the server’s database. Based on what the user selects, the page is created on the fly by the server with content from the database. You would need only a few landing pages populated with menus & scripts. The server takes care of the rest. 

Hope that helps.

Your question is still very broad.

You mention the site, but you do not point to a specific Dreamweaver problem, a specific page, or a specific part of the workflow that is failing.

For a site with many calculators, the general advice is to avoid duplicating hundreds of hand-built pages. Use Dreamweaver Templates for the common structure, shared CSS for the design, shared JavaScript for common behavior, and keep each calculator's specific formula separate from the shared code.

But without a precise issue, it is difficult to give more than general advice.

If you have a real Dreamweaver problem with templates, reusable code, Git integration, site management, or file synchronization, please describe that specific problem and show the relevant page or code.

Otherwise, posting a general workflow question with a site link can easily look more like traffic generation than troubleshooting.