A lot of people said good points, I will just underline one thing that you mentioned about reaching people/companies via a language/tech. I find this quite a double-edged sword because do not forget that the people/companies that provided you an opportunity just because a tech stack is trendy, will not refrain from putting you out of a job once another trend is getting traction.
I'm sure there are companies out there that value deep vertical knowledge about a specific topic. Follow your passion, not the trends. (this is hard, very hard given the conditions in life, but not impossible)