Simple enough-the extract_multiple() function can apply multiple functions or regular expressions to do so. Changing the extract_multiple() line to the following:
@extracted = extract_multiple( $str, [ \&extract_quotelike, qr/\s+/, ], );
results in the following output:

Input:  50 0 "R0 G255 B0 A255" "Solid" 118 1 "R0 G0 B0 A255" "R0 G0 B0
+ A255" 0
Output:
        50
        0
        "R0 G255 B0 A255"
        "Solid"
        118
        1
        "R0 G0 B0 A255"
        "R0 G0 B0 A255"
        0
Input:  70 0 "R0 G255 B255 A255" "Solid" 118 1 "R12 G12 B12 A255" "R12
+ G12 B12 A255" 0
Output:
        70
        0
        "R0 G255 B255 A255"
        "Solid"
        118
        1
        "R12 G12 B12 A255"
        "R12 G12 B12 A255"
        0
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(My original code was just extracting based on the quotation marks as delimiters.)

Hope that helps.