Software people use for self-publishing and where to look for professional help

Before asking my main question, let me point out that in some sense *all* publishing is self-publishing. For example, textbooks and other educational materials often have accompanying online resources -- sometimes entire websites for a single book -- with study questions, interactive lessons, or other supplemental content. Also, many publishers encourage (or even require) some sort of "data availability" or "transparency" statement such that authors must create and deposit research data sets on open-access sites like OSF, github, etc. Publishers however provide minimal support for these projects; so, in effect, authors are self-publishing their "research objects" even if their original book or article is paywalled.

Besides, with houses outsourcing editing, indexing, and so on to outside companies (often with dubious results) more and more of the work seems to fall on authors' shoulders. I was just helping an author prepare a manuscript for Oxford University Press, and she summed it up as: "I've basically self-published this book. OUP hasn't contributed much beyond printing and promotion." Her copy-editor created a lot more errors than they corrected.

I personally have both written academic books and articles and helped others at various stages of the publishing workflow. Over the years I've developed publishing software that I've modified for each individual project, helping me automate some editing, indexing, and compositing tasks. My observation is that many authors need specialized technical help whether they self-publish work more traditionally. They might have an MS Word document but don't really understand how to create professional PDFs, LaTeX, JATS-XML, Executable Research Objects and so forth.

And yet, I have not found particularly useful sites where authors could go to find either computer software or outside help for tasks like editing, indexing, or compositing. Partly I'd like to connect with authors to facilitate self-publishing, not only for commercial reasons but also so I could refine and enhance my software (I have in the past and hope in the future to work on a purely volunteer basis for nonprofits). I know we cannot self-promote on this subreddit so I'm not trying to present personal details, but I would like to find web sites devoted to self-publishing where I could create a profile.