We just started exploring Mise as a (much) simpler alternative to Nix + Bazel for a polyglot monorepo.
One of my concerns was about how well maintained Mise would be given that it's mostly a single maintainer, so I think this is good news in that respect.
Congratulations! I think that a lot of the value will be in the judgement of the maintainer about the marginal next feature (and saying no to all those other features) ... if software is a stream then the value is in what gets into the stream. That is an AI resistant value and if you can provide it for your project.
Good luck, and I hope it works out! Make sure you are ready to ride the roller coaster of highs and lows, as there are going to be many. Remember that your time and experience are the most valuable things you have - make sure you're in control of both.
One of my concerns was about how well maintained Mise would be given that it's mostly a single maintainer, so I think this is good news in that respect.
Good luck to Jeff!