I can currently only do 2a03 in Furnace Tracker, is it accepted to submit .fur files instead of an .nsf in that case?

unfortunately no, the format is restricted to .nsf only, due to the ability to play those files on real hardware. check out famitracker if you can! it's pretty easy to use and a lot of stuff should carry over from your furnace experience

You might be able to export NSF from Furnace

someday. Consider joining the discussion to let your voice be heard.

I vote to continue the game on the same save file 🙏

Vote:
continue on the previous game file (like this comment)

or start a new game from the beginning (hate this comment)