plotting – Generating PlotLabel with mathematical formatting

What’s a good pattern to insert properly formatted matrices into PlotLabel? I’m trying to insert something like the following into my plot, where the matrix is programmatically generated.

$$
f(x,y)=
left(
begin{array}{cc}
x&y
end{array}
right)
left(
begin{array}{cc}
1.00 & 0.00 \
0.00 & 2.00 \
end{array}
right)
left(
begin{array}{c}
x \
y \
end{array}
right)
$$

Doing PlotLabel->MatrixForm(mymatrix) displays the matrix part properly, but how do I concatenate it with the other bits?

rotatedAxes(angle_) := (
   H = With({r = RotationMatrix(Pi/4)}, 
     r . DiagonalMatrix({1, 2}) . Inverse(r));
   f({x_, y_}) = {x, y} . H . {x, y};
   
   rotmat = RotationMatrix(angle);
   xaxis = rotmat . {5, 0};
   yaxis = rotmat . {0, 5};
   Hdisp = 
    Map(NumberForm(#, {3, 2}) &, 
      N(Inverse(rotmat) . H . rotmat), {2}) // MatrixForm;
   
   ContourPlot(f({x, y}), {x, -2, 2}, {y, -2, 2}, 
    ContourShading -> None, Contours -> 15, 
    ContourStyle -> Directive(RGBColor(0.5, 0.5, 1)), Frame -> None, 
    AxesStyle -> Directive(Black),
    Epilog -> {
      AxisObject(InfiniteLine({{0, 0}, xaxis}), {-1, 1}, 
       TickLabels -> None), 
      AxisObject(InfiniteLine({{0, 0}, yaxis}), {-1, 1}, 
       TickLabels -> None)},
    PlotLabel -> Hdisp
    )
   );
rotatedAxes(Pi/4)

enter image description here