Rails has so much to offer these days, going vanilla really is a viable (and enjoyable) option. Here at Swivel we use the ENTIRE rails stack from Hotwire to Kamal and it is so simple and easy to maintain and deploy. I do think there are use cases where adding a React frontend is good though. But you don't have to, Rails has everything you need so you can focus on creating value for customers instead of plumbing.
They actually just released a new, rubust getting started guide that is an EXCELLENT place to start learning the framework: https://guides.rubyonrails.org/getting_started.html. I highly recommend starting there.
The new getting started guide is great. Chris Oliver is a great teacher. Afterwards, if you want a 102-style tutorial, I'm a big fan of https://www.hotrails.dev/. It goes step by step and explains how Hotwire works and how to use it.