Adjusting cells height per row and, thus, simulating a table isn't too difficult, but perhaps what follows has its own hidden drawbacks. Thanks for reminding about Prima and GUIs in general, nice time it was.

use strict;
use warnings;
use feature 'say';

use Prima qw(Application Label InputLine);
# use Prima::Stress;

my $main = Prima::MainWindow-> create(
    text => 'Configuration',
    backColor => cl::White,
    menuItems =>
    [   ['~File' => [['~Quit' => 'Ctrl+Q', '^Q',
                   sub { $::application->close } ], ],
     ],
    ]
);
$main-> hide;

my $table = $main-> insert( 
    Widget =>
    pack => { side => 'top' },
);
my @cols = map $table-> insert( 
    Widget =>
    pack => { side => 'left', anchor => 'n' },
), 0 .. 1;

# let's pretend columns do have different scale
$cols[ 1 ]-> font({ size => 5 + $cols[ 0 ]-> font-> size });

for ( 0 .. 9 ) {
    my $label = $cols[0]-> insert( 
        Label =>
        text => substr( 'Label 1234567890', 0, 7 + $_ ) . ': ',
        pack => { side => 'top', anchor => 'e' },
    );
    my $input = $cols[1]-> insert( 
        InputLine =>
        text => '12345',
        pack => { side => 'top' },
    );
    
    my $h_L  = $cols[0]-> height;
    my $h_IL = $cols[1]-> height;
        if ( $h_L > $h_IL ) { 
        $input-> pack( pady => $h_L - $h_IL )
    }
    else {
        $label-> pack( pady => $h_IL - $h_L )
    }
}

$main-> show;
Prima-> run;
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