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.
Good luck to Jeff!
As a proponent of both Nix and Bazel, unless you need them for a specific reason you should totally use Mise. I recommend Mise to everyone.
If everyone on your team gets Mise and you're starting to feel pain at the periphery then it can definitely make sense to adopt a more elaborate toolchain orchestrator.