While I do have sympathy for you, OP, I’m going to advise you to man up a bit here. Your mom can’t dis your wife unless you want to get a divorce. Seriously, your spouse is supposed to have your back against everybody - even their parents. ESPECIALLY their parents. Your mother should have no standing in your relationship with your wife. Her opinion should count for zip. Your wife, the mother of your children, needs to come first on the list, period.
That your mother would suggest otherwise is eye-rollingly obnoxious. My son is 1. One year old and even I know that eventually I’m going to be usurped as his favorite person. Maybe I won’t like who he chooses, but assuming that person is good to him and makes him happy then my job as a good mother at that point is to be kind, supportive, and friendly with the person and complain horribly to my girlfriends after the fact. The moment I start disrespecting that person to their face or to my son, I’ve officially become an asshole.
Sorry OP, your mom, as much as you love her, is the asshole in this situation and your job as a husband is to protect your wife from her toxicity. Ditto for your daughter. Should your mom get to meet her granddaughter? Probably, but for your daughter’s sake - not your mom’s. The moment the relationship quits being good for your daughter it ends, and your mom can get stuffed.
And seriously, if your mom acts like an asshole and tells you it’s because she’s Italian, tell her to quit being a racist.