Since you have experience, most tutorials are just going to be boring. I would focus on 3 things:
1. Work through some books that dig deeper into technologies you already know. This will help you re-familiarize without being too simple. For RoR, I would look at Ruby Under a Microscope, Rebuilding Rails.
2. Just write code. Get back into thinking about different approaches, and explaining the pros/cons of each. Some of this could be leetcode style for interview prep(advent code starts in a few weeks). But also just building apps in Rails. If you don't have any ideas, just go through the standard "build your own X", where X could be twitter, instagram, reddit, etc.
3. Review your resume. Go back to thinking about what you did in your last job. It's likely, with a break, that you can't easily remember what you accomplished at previous roles. If you start thinking ahead of time you can work to recover some of those memories. Start building the stories around them so you'll be ready for the "tell me about time that X" questions/discussions.
