Is it worth publishing a paper rephrasing what past papers did with a different mathematical framework?
Here is my opinion and suggestion (I claim no authority).

Elegant derivations are of indisputable value, even if they are mathematically equivalent to existing results. Think of postgraduate students reading your paper and having an &quot;aha&quot; moment, for example. By contributing elegant results, you are promoting your sub-field, which could be appreciated by other researchers.
I won't be able to suggest a journal, unless we work in the same area. I doubt it is possible at all without knowing the details. There probably exists an applied mathematics / engineering journal dedicated to your topic, which leans towards mathematical aspects and has many non-experimental papers. If you want to submit a concise paper, perhaps, look for the word &quot;communications&quot;.
If searching by keywords in Google Scholar or similar doesn't yield what I want, I try the following. Crawling citations from the most relevant papers or books / volumes / series / conferences. Checking publication lists of the most relevant researchers / labs. Reading theoretical chapters of doctoral theses, which can be a good source of carefully chosen references.