Great writeup. Minor comment about the portion of the post mentioning Conda being glacially slow: Mamba [1] is a much better drop-in replacement written in C++. Not only is it significantly faster, but error messages are much more sane and helpful.
That being said, I do agree that Pkg.jl is much more sleek and modern than Conda/Mamba.
Conda should have set the default for channel_priority to strict a while ago, it significantly reduces the search space [0], and it reduces the chances of the solver finding a poorly-specified-yet-nominally-compatible package build on some less rigorous channel. With strict channel_priority and conda-forge as my priority channel, it hasn't taken more than maybe a minute for to solve any dependencies (assuming the target packages are on the priority channel) for any of my own envs, although when I try to recreate envs that installed packages from many channels, I have experienced some long waits.
That being said, I do agree that Pkg.jl is much more sleek and modern than Conda/Mamba.
[1]: https://github.com/mamba-org/mamba