I don’t know how true it is, but I read in another thread recently that Planck mass is about the mass of an eyelash and also the minimum mass of a black hole. Below that mass the location of a particle isn’t localized enough for it to be a black hole. Also IIRC the Schwartzchild radius of such a black hole is something like twice Planck length.
I don’t believe that’s correct. At least, the last time I looked into it, the sources I looked at specifically said that version is oversimplified to the point of just being wrong.