How do I put text above and under an expression?

I’m trying to outline something in a function, by putting text under and above the equation. Text under the equation works fine, but the text above the equation is moved to the right of the equation, which is maybe normal for powers, but I hoped it would behave the same as how it works for sum signs.

begin{align} 
Biglangle hat{A}(t) Bigrangle_S &= int U_m^*(vec{r}) hat{H}     U_n(vec{r}) dd^3 r
& = displaystyleBiglangle 
underset{text{color{darkgreen}Time independent}}{displaystyle
    {displaystyle{color{red}overbracket[1.2pt]{color{black}psi_S(t)}} 
        color{black}Big| 
        color{darkgreen}underbracket[1.2pt]{color{black}hat{A} Big|}
        color{red}overbracket[1.2pt]{color{black}psi_S(t)}
    }displaystyle^{text{color{red}Time dependent}}
} Bigrangle
end{align}

I also thought that maybe there was a thing that works similar to underset, but then puts the text above the equation. I tried both overset and stackrel.

```
begin{align} 
Biglangle hat{A}(t) Bigrangle_S &= int U_m^*(vec{r}) hat{H}     U_n(vec{r}) dd^3 r
& = displaystyleBiglangle 
underset{text{color{darkgreen}Time independent}}{displaystyle
stackrel{text{color{red}Time dependent}}{
    displaystyle{color{red}overbracket[1.2pt]{color{black}psi_S(t)}} 
    color{black}Big| 
    color{darkgreen}underbracket[1.2pt]{color{black}hat{A} Big|}
    color{red}overbracket[1.2pt]{color{black}psi_S(t)}
}
} Bigrangle
end{align}

It does (somehow) print the same output as shown above, but it gives me an error message. For overset:

Limit controls must follow a math operator.
overset ...nrel@@ {mathop {kern z@ #2}limits 
                                              ^{#1}}

as well as for stackrel:

Limit controls must follow a math operator.
stackrel #1#2->mathrel {mathop {#2}limits 
                                          ^{#1}}

I have no clue what that means, or how I should write the code so that it does the thing I want. Also, does anyone know where overset and stackrel are useful for, as it apparently can’t do the thing I want it to do?

& = displaystyleBiglangle 
underset{text{color{darkgreen}Time independent}}{displaystyle
    raisebox{20pt}{parbox{0cm}{text{footnotesizecolor{red}Time dependent}}}{
        displaystyle{color{red}overbracket[1.2pt]{color{black}psi_S(t)}} 
        color{black}Big| 
        color{darkgreen}underbracket[1.2pt]{color{black}hat{A} Big|}
        color{red}overbracket[1.2pt]{color{black}psi_S(t)}
    }
} Bigrangle