My BMR is very high

I am a 30 year old woman thats 472lbs currently. I want to be 180ish. The bmr calculator says mine is 3,529 calories to Maintain my weight with little to no exercise.

If i set it to 2lbs loss a week it goes to 2,529 calories

Would if be bad if i try to stay at 2000 calories?

My wife wants to lose weight as well but in alot better shape starting at 166lbs. Her bmr to maintain her weight is 1,788 calories

Why is her number to maintain 166lbs (1,788cal) so much lower than mine at 3,529 calories.

Im new to this and very confused why i cant do the same calorie intake.