Having a website that works well on ALL devices [Responsive Web Design]

Short answer:  No.  Responsive design begins at the planning phase, not at post-completion.  Sorry.

Long answer:  Start over with one of the pre-built Bootstrap starter Templates in Dreamweaver.  Bootstrap is mobile-friendly and performs well on all-size devices -- small, big and everything in between.  And it will cut your site creation time in half so you can focus more on content instead of architecture.

Go to Site > New Site and define a new local site folder.  C:\MyNewSite

Go to File > New > Starter Templates > Bootstrap Templates.  Choose a Sample Page Layout and hit CREATE button.

Save as index.html (your home page)

Dreamweaver will create the starter site folders & scripts for you in your Files Panel (F8).

See screenshots.

Replace starter text & images with your own.  See links below for reference tutorials.
- https://www.w3schools.com/html/
- https://www.w3schools.com/css/
- https://www.w3schools.com/js/

- https://www.w3schools.com/bootstrap/

NOTE: As of this writing, the current Bootstrap version is 5.3.  You can obtain the latest CSS & JavaScript bundles from Bootstrap's Official CDN (Content Distribution Network) below.

https://www.bootstrapcdn.com/

Or simply replace references to Bootstrap scripts in your document to these:

CSS - https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/css/bootstrap.min.css

JS - https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/js/bootstrap.bundle.min.js

Hope that helps.

I am sorry to be the bearer of bad news; Dreamweaver does not 'fix' anything. All it will do is help a developer to create a website. It is a tool.

To find out more about responsive web design, see https://developer.mozilla.org/en-US/docs/Learn/CSS/CSS_layout/Responsive_Design

You could use a responsive framework like Bootstrap to make life easier,