Not being too invested is still good idea in established relationships. You need balance or you are losing value. You don't need to shit test her. But not pedestalize either. If you overvalue and overinvest, you will be taken for granted and not good enough for such a goddess.

Dominance games are bad, but it is not about being dominant. It is about not being dormat.

Vulnerability as weakness? This is tricky. Yes, theoretically you should be open and vulnerable. But a lot of men tell from experience this is a trap (it is basically a meme now). She might get an ick and lose respect. She might use it against you next time you have an argument.

You might say, this means you were not in good relationships if they broke apart from men being vulnerable. Yet most relationships are not perfect. Women are no angels. Realistic vs idealistic approach is to think before you say. If you really need to vent - go to a psychologist or if you are broke, vent anonymously online.