1. Your frontend js needs are pretty minimal and you don't want something approaching a single-page app. In this case, you lean into Turbo and Stimulus to have rails do most things for you that would previously have been done with some a heavy-weight react-based frontend.
2. Your frontend js needs are significant and you do want a single-page app. In this case, ignore/disable turbo + stimulus. Instead, build your rails app as just a json API and then have a separate project for your frontend built using a dedicated frontend build tool like vite/CRA/webpack/etc.
On one hand, I feel like the turbo/stimulus stuff is the rails community preferring to pretend that the JS world doesn't exist. On the other hand, maybe it's really just the rails world embracing the above dichotomy: they're tools for doing some light frontend work with no JS, and an acceptance of the fact that if you want an SPA, there are better non-rails tools that you'll wind up using anyway.