Well, if you went to Yeshiva the following should be clear.
A statement of Chazal of such a nature will often be questioned by the meforshim and explained in a manner different enough from the superficial meaning to warrant what I wrote. While this statement clearly has practical ramifications relating to laziness, I’m confident in my assumption that I can easily find a mareh makom explaining it in a way which would make it far more ‘palatable’ for you.
2)I have no issue with a statement of Chazal which says a common character deficiency of women. There are plenty about men, and plenty of praiseworthy ones about both genders too. This has nothing to do with either one being intrinsically inferior. As they have different natures, it only makes sense that they have different flaws, with different ramifications.
3)You may not understand the Rambam or Gemara, but it says nothing, in those cases, of being dumb or untrustworthy. Nor am I aware of the Halacha having changed