I write an SPA for my day job. I write Postgres queries myself. I create endpoints and background workers and cron jobs myself, and I build out the UI myself. It’s all typescript with static types end-to-end. It’s a fantastic developer experience. Much, much better than I ever had in Rails or ASP.NET.

Also, I love components for UI as opposed to templates. And I don’t think I could ever really go back to the way I did things in my MPA days.

If there's no clear backend/frontend split wrt to language and roles in your particular project my point doesn't really apply for you. But it seems that you're lucky that you can use js on the backend to get closer to that. I would still prefer to not have to do a SPA unless obviously required for the job, but at least you got some of the fundamentals in place to be individually productive.