This is just an expansion on the great answer from @EdMorton for anyone who wants to wrap it, as a a proof of concept this works:

#!/bin/bash

func() {
        echo "test...stdout - arg 1: $1 - arg 2: $2"
        echo "test...stderr 1" >&2
        echo "test...usrerr" >&4
        echo "test...stderr 2" >&2
        return 1
}

wrap() {
        func_name=$1; shift; func_args=$@

        { em=$($func_name $func_args 4>&2 2>&1 1>&3-); ec=$?; } 3>&1
        
        if [[ ec != 0 ]]; then
                echo "Error code: $ec"
                echo "Captured stderr (not shown):"
                echo "$em"
        else
                echo "There were no errors."
        fi
}

wrap func abc xyz

And the result is:

test...stdout - arg 1: abc - arg 2: xyz
test...usrerr
Error code: 1
Captured stderr (not shown):
test...stderr 1
test...stderr 2