I was under the impression that the idea was “Vite by default, other build tools supported, because it’s all just JS” but I’m not sure if that’s still the plan or not or how much work it is from here to make it generally compatible.
We’re still putting the polish on moving to Vite (mostly docs remaining). Sometime in the 7.x series we plan to deprecate building with the classic Ember build pipeline, but before that happens there will be an RFC to do so posted on GitHub - emberjs/rfcs: RFCs for changes to Ember · GitHub