Peach x Bowser is canon, sorry OP.
Peach is attracted to Bowser, because he's the bad boy. Which explains why she keeps getting "captured" by him.
Then every time she realizes that bad boys are bad for relationships she'll call on nice guy Mario, to "rescue" her.
Like a good simp Mario rises to the occasion, in hopes that this time he'll get a handy, only for Peach to give him a hug and tells him how much she values their friendship.
Then when she inevitably gets bored of Mario, Peach will have bad boy Bowser give her the excitement she craves.
The cycle repeats...
College level drama trash.
None of these characters ever grow up.
At least we can enjoy their endless misery.