There’s no question that the Jewish tradition of bathing for purification is the direct historical source of Christian baptism.
Specific practices and spiritual contents vary among Christian denominations.
And, again no expert in the female side, but men have to be extremely clean before getting into the Mikva. As in, a scrub down shower, nails and cuticles cut, etc.
I’m fairly confident it’s the same for females, but I will ask my wife.
Never asked. Seemed private to me.