Hi there,
These days, with all the hiking apps (Komoot, Wikiloc, etc.) and accommodation addresses easily found online, it's super easy to skip guides and agencies for a "trek" (let's say a simple hike here) that goes just a little off the beaten, overly classic, and not-so-interesting paths.
For example, with Komoot, here’s the kind of easy hike you can do without an agency:
https://www.komoot.com/fr-fr/smarttour/17059498
Just download the route—it’s free!
You’ll find other longer and more interesting routes by poking around the apps. Local agencies, for convenience, always offer the same overcrowded and over-touristed options without much originality... I tried it once in Myanmar (it was almost mandatory), and I won’t be doing that again!
P.S. I crossed this entire region on foot from Banawe to Bontoc back when there were no agencies on Luzon, paper guides were just a few lines long, and all the maps were wrong.