Templates are proprietary to each WYSIWYG editor. They are NOT uploaded to - or part of - your website. You should not expect any editor to be able to use DreamWeaver templates, unless they have EXPLICITLY stated that it can.
These template-based editors generate HTML, which is what you upload to your website. Templates are a tool for MAKING your website - not a part of it.
You should CERTAINLY not expect any editor to reverse the process, and be able to somehow magically produce the template (in a kind it doesn't understand) from the HTML!
I think it's really good to struggle with a plain text editor for a while, so that you come to some understanding of HTML. For example, you said earlier, you can't use a text editor, because you need to "change images".
If you need to use a DIFFERENT image, you only need to put the image in the right directory, and change the file name in e.g. <img href="my_cat_picture.jpg"> change to <img href="my_other_cat_picture.jpg">
If you need to edit the content of the picture itself, you need an image editor! Fortunately, you don't need Photoshop, as decent free/cheap/good image editors are relatively more plentiful than decen free/cheap/good WYSIWYG HTML editors.
The problem for publishers is that this is an old-fashioned way of making web pages, and probably a shrinking market.
The trend today is definitely toward builder-in-the-clouds solutions like SquareSpace, Wix, etc. and also toward working in a text editor. But a fancy text editor that does nice syntax coloring, auto-completion of HTML/CSS/JS, and a preview mode that will instantly show you the result. You might consider this "semi-WYSIWYG".
I feel your pain... you've invested time and energy into developing some sites with dreamweaver, it is fairly costly, and there really is no easy way to transition from dreamweaver to something else seamlessly.