I’m fairly sure there is more to it from a technique perspective. Works like the Visuddhimagga and the Vimuttimagga explain the whole “focus on one thing / focus on breath” thing in extraordinary detail, and I consider these basically a forgotten technology. I have found these micro-steps to be really helpful in learning to meditate more deeply but are almost entirely ignored in the Western explanations and meditation apps.

That said, the traditional texts are still hard to parse. I’ve considered writing a manual-to-the-manual of sorts that explains the same concepts but in a modern way. I should mention that Leigh Brasington has some really awesome content out there (videos, books, and articles). I am not a master meditator, but if that sort of a thing exists, Leigh is.

Others who have explained mindfulness of breathing in a modern way are Bhante Gunaratana, Bhikku Analayo, Culadasa, Larry Rosenberg, Bhikku Buddhadasa (though his take is unconventional), Michael Taft, etc.

But as you have said there are many more techniques. I've heard the breath called a relatively difficult meditation object for beginners.

All I heard is a bunch of obscure references and name dropping. If there was a clear technique, one would be able to outline it like outlining the steps to deadlifting correctly.

There are many techniques that work. They can all be clearly outlined as well, but that is more work than I'm willing to undertake here. The names I dropped (as you kindly put it) have done all that work and compiled their efforts into well thought out, well written, well edited and well reviewed books. There are a lot of nuances and individual variations on problems that come up and how to get past them that all these books address.

But you have to make the effort of reading the books (or finding a competent teacher) and then practicing the techniques hard enough and long enough for a fair appraisal. 10 minutes a day of instructions from Headspace is predictably useless. You can write it off at that if you like, but it would be like pumping a dumbbell for two reps a day and concluding that weightlifting is useless as exercise.

To many, there are life changing effects, from being generally more aware to being more calm or sleeping better. Clearly, if for you it doesn't do any of that, you're one of those who cannot benefit from meditation. But you may never know if you're inadvertently not doing it right. So many times in my life I thought I was doing something right only to discover much much later that somehow I was doing it the wrong way.

If you think it’s easy to focus on one thing, you haven’t tried meditation.