I’ve seen a number of people move from .NET or Node to Ruby and Rails and thoroughly enjoy it, with little desire to go back. For reference, the last 12 years I’ve worked for a company that was traditionally .NET. In the past few years, we’ve been choosing Rails instead. Once you know its conventions, you can really fly. It’s very mature and doesn’t often change in frustrating ways. What I learned in 2014 is still very relevant today.
Especially on small teams or solo, it’s amazingly productive. The out-of-the-box experience gives your users the feeling of a modern SPA without actually being one. Instead, it’s built like a .NET MVC app with standard resource rest routes and Razor views. Significantly less boilerplate. Hard to describe, but very clever. It makes me feel powerful, and I really enjoy programming with Ruby.
But maybe it’s not what you’re looking for if you want a single final frontier to ride off to. Some people really dislike Ruby’s dynamic nature, and Rails’ mysterious-seeming clever conventions. (Though, note, it’s not magic, it’s just clever Ruby code. Everything can be traced and explained). Other languages have a larger market share and perhaps more excitement. But, your described use-case of solo web-dev moots that point.
Consider looking through https://rubyonrails.org/ to sniff it out. Watch that video to see if it jives.
https://gorails.com/guides is a great resource to learn how to set up a dev environment, with tons great modern content.
Whatever you choose, good luck. I hope you find a great fit!