As another example of an adjacent community effort, there is the Seven Day Roguelike Challenge every year, where participants make a Roguelike game in seven days. If you think of your Nethacks and Angbands that have gestated over decades, this seems impossible. But the common advice is to have your tools ready. These are not the place to try out new technology or tackle particularly technical problems. Have a single idea and execute it.
So I think the idea is: have a framework ready, have it ready to build, have a scope, probably halve that scope and then write like the Dickens.