From a 1st tier publisher. ;) But I concur with another comment, it's hard to justify not going with self-publishing in 2019. More so if you're not doing this for money. I would prefer to publish a completely free ebook (like Pro Git, etc.), but it's hard to negotiate this with traditional publishers.
I am skeptical on the point that a good publishers adds no value.
In our case, we authors have been publishing papers for over a decade. And together we have almost 1000 citations for our papers.
And yet, we were not able to think over and improve on certain aspects of a book that we discovered only after talking to our current publisher.
Maybe if you are completely clear on what your book is about and how will readers react to it, a publisher might not matter. But for us, it seems it was not the case.
Even if you are expecting financial gains self publishing is still very valid. (I am talking from personal experience where my self published tech courses make more money that my editor published ones). Dont forget that even though editors do the marketing for you you only get a small fraction of the total sales. And also they might not be very good at the special niche you are targeting.
From a 1st tier publisher. ;) But I concur with another comment, it's hard to justify not going with self-publishing in 2019. More so if you're not doing this for money. I would prefer to publish a completely free ebook (like Pro Git, etc.), but it's hard to negotiate this with traditional publishers.