While I don't know which (if any) Python package manager will "win", I'm confident it won't be Conda or similar. I hope and pray not, anyway.
Iff it must be the conda ecosystem, pixi (https://pixi.sh/latest/) is a much better pick.
But conda-style packages (or anything with install time dependency resolution really) also have the issue of being completely untestable. That makes them unsuitable at least for user-facing package management, if you care about your packages not randomly breaking without warning.
I'd rather see every language converge on a single package manager that implements functional package management, i.e. guix or nix. One can dream...
I've found that there really only are two kinds of packages I want to install: those I want globally (e.g. CLI tools like git, git-annex, DataLad, whatever shell enhancing you want, etc.) and project-specific dependencies (anything required to get going with it on a freshly installed system with the smallest amount of assumptions possible).
The former is sufficiently addressed by `pixi global` and other package managers, the latter by pixi projects. Notably, conda environments are a bad fit for both (not global, not really updatable, not automatically tied to a project, not rebuildable due to missing lock files, ...).
You could just as well install it either globally with pixi global, or as a project dependency in a pixi project. In this case, the latter.
> I also have a few shared envs, for quick tests
Fair, I just use temporary directories with pixi projects for that and thus no longer see a point in conda envs for this. It has the added benefit that all my temporary directories are in the same location and easy to get rid of.
> general utils
I would want those to be available at all times, so conda envs aren't fit for that purpose. Instead, I use pixi's global subcommand.
> Poetry for project management.
That limits you to lock files for python dependencies only, unfortunately. In a project relying on browser automation, I would want the browser version to be recorded in the lock file as well. Pixi does that.
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I still don't really see why you found pixi lacking. It addresses all of your problems, maybe with the exception of globally installing multiple and non-CLI packages. But again, conda isn't any better as you are generally advised not to install stuff into the base env and conda has no other facility for globally installing general utilities.