Parentheses or brackets size adaptation in display math

[Omikhleia]

Standalone parentheses or brackets in (display) math automatically adopt a "big" scale if needed around content:

\math[mode=display]{(\frac{a}{b})}

However, they lose this capability if the expression gets (subscript or) superscripts, e.g. gets elevated to some power:

\math[mode=display]{(\frac{a}{b})^2}

Adding extra brackets around the parenthetical part sort of works, but the power is not raised higher (as e.g. TeX would do after a \bigg)) so it doesn't seem to be a fully satisfying workaround:

\math[mode=display]{{(\frac{a}{b})}^2}

My expectation (image manually tweaked) would have been:

Is there a proper way to achieve it?