As others have noted, the new program isn’t changing anything for Scrivener users, so there is nothing to worry about there. It’s an entirely different program, like Scapple is.
As for the connection you speak of, for that to change it would take a fairly fundamental destruction of the compile system for that to happen—in so far as we are speaking of what the compiler can do to help us automate or avoid direct syntax as a general concept. Of course, at its most basic level LaTeX is just a typing convention, and one doesn’t need any features at all to use it other than a keyboard and a program that stores what you type. So of course what most are thinking of is what the compiler can do to do that typing for you. Styles, section layouts and other such tools are what make the LaTeX template work, and that’s it.
I made that template because it is a popular typesetting system, particularly in some fields, but we might expand that to other systems in the future as they mature.
The main thing to know is that there isn’t a single line of code in Scrivener that knows about LaTeX other than one check on launch that looks for latexmk (which if found, enables a MultiMarkdown → PDF convenience selection to the Compile For menu). The template is wholly responsible for that connection, and everything it does could be used to make another kind of format entirely, like XML-based output for DocBook, or ReStructuredText+Sphinx for Python documentation, Typst, Quarto as mentioned, etc.
So again, for that to stop working, Scrivener would have to, to some degree, stop being Scrivener—and its not going anywhere. In my opinion this is the best way for software to approach these kinds of formats. Unless it is very specificaly a “front end” for them, like LyX, it is better to provide a framework of tools that allow users to create formats, than to try and do all of that centrally with hard-coded assumptions (for example, using XeLaTeX instead of LuaLaTeX).
P.S. Nice to see you back. 