publications - Pros and cons of (co-)authoring a reference book in early career?

I am early in a tenure-track position. I undertook with a publisher to write a reference book a while back and with a light load to start with in my new position, I recently agreed to set a deadline of later this year.

I progressed quickly through some of the core chapters where I knew what I wanted to write.

Now I have a heavier teaching load, preparing course material from scratch week-to-week, and am struggling to cope with my work hours.

But spending all my few spare cycles in the book seems to be carrying a huge opportunity cost. Though my research profile is sufficiently strong for me not to have to worry about journal output for a while, and I'm currently in the "harvest cycle" of a couple of journal papers that are coming through from about a year ago, I feel I am missing opportunities to start collaborations with other faculty members. I want to start on some new directions and target new communities with the help of new colleagues.

Furthermore, I feel like I don't have the bandwidth to bring the quality of the book to the level I would like. Writing the book has thus become a disheartening chore, trying to balance progress and quality. Working odd hours here and there, I can't dedicate myself to it. There are more pressing things to think about while showering in the morning. Every time I go to work on it, it's a cold start.

In this rather excellent answer on an unrelated question, @Pete L. Clark mentioned the following:

With regard to writing books: one of my most distinguished colleagues, Dino Lorenzini, wrote an excellent and rather successful book near the beginning of his career. He now tells anyone who will listen that junior faculty should not write books. Of course sometimes the heart wants what it wants, but from a strategic perspective I think this is eminently sound, and I say this as someone who may turn around and write some books now that I am solidly into my mid-career.

This prompts me to ask, is it generally the case that writing a book early in one's tenure-track career carries too much of an opportunity cost? My hope is that the book will stand in good stead for my tenure application, and may attract citations in the long term (I believe it is in a good niche), but would I be better off with two-to-three more good journal papers instead (what I estimate the opportunity cost to be)?

Essentially I'm looking for anecdotes on how writing a book helped/hindered early-career (tenure-track) researchers.