Braces around a tikz node (for example: "{text}" instead of just "text")

I wrapped things in styles in the code below, but that is not required.

The reason there is so much air between node text and braces is the text width of the nodes, that can be modified in various ways, for example by using node[align=center] (R) at (-3,0) {Radicalideals of $A$}; instead, then the node becomes only as wide as the longest line.

documentclass[border=1cm]{standalone}
usepackage{amsmath}
usepackage{tikz}
usetikzlibrary{decorations.pathreplacing, arrows.meta}
begin{document}
begin{tikzpicture}[
  Brace/.style={
     thick,
     decoration={ % define decoration
        brace,
        amplitude=5pt % height of curl
        },
     decorate % activate decoration
  },
  FuncArrow/.style={ % style for the lines
    -{To[length=3pt]}, % add arrow tip
    shorten >=8pt, shorten <=8pt % shorten the lines a bit so they don't crash with the braces
    }
]
 
node[text width=2.65cm,text centered] (R) at (-3,0) {Radical ideals of $A$};
node[text width=2.8cm, text centered] (C) at (3,0) {Closed subsets of $operatorname{Spec} A$};

% modified the style here, and swapped the drawing coordinate order of the second one
draw[FuncArrow,transform canvas={yshift=0.15cm}] (R) -- (C) node[midway,above]{$V(cdot)$};
draw[FuncArrow,transform canvas={yshift=-0.15cm}] (C) -- (R) node[midway,below]{$I(cdot)$};


foreach nodename in {R,C} { % draw braces for both nodes
% the order of the coordinates matter, one is drawn from north to south, the other from south to north
% (there is a mirror option for the brace decoration, but that would need two different decorations I think)
draw [Brace] (nodename.north east) -- (nodename.south east);
draw [Brace] (nodename.south west) -- (nodename.north west);
}
end{tikzpicture}
end{document}