Best web dev stack for long-term open source SPA

I would like to be able to live the dream: develop an open source app, long term, while staying sane.

I’m moving on to a new stage of my academic career and want to invest in learning a new tech stack for building open source web apps. Preliminary choices:

“Sign in with Apple”, ZEIT (less sure), Tachyons, Discourse-based messaging

Look right? Or any other suggestions for “must be free, open source, and not require an email to log in”?