Updates work about half the time for me on mini-conda, but they break the other half of the time. When I look up the issue, I am not alone. I end up re-installing it a lot.
I have had this happen a few times too. I have found the best way to minimize this is to install nothing in the base environment except for conda and make sure you use a different environment for everything else.
Secondly, the vast majority of solutions offered by the many people who face similar issues don't work for me or, apparently, for other people reading the solution as well.