Solution:
@foreach ($items as $item)
<div class="print-block" style="page-break-inside: avoid;">
<div class="print-block__img">
<img src="" alt="">
</div>
<div class="print-block__details">
<h3>{{ $item['item_description'] }}</h3>
<div class="code">{{ $item['amt_item'] }}</div>
<div class="price">
<strong>W:</strong> USD {{ $item['wholesale_price'] }} | <strong>R:</strong> USD {{ $item['retail_price'] }}
</div>
<table class="other-info">
<tr>
<td>
<strong>
Sizes:
<?php
$uniqueSizes = [];
?>
@foreach ($item['color_size_grid'] as $color => $sizes)
@foreach ($sizes as $size)
@if (isset($uniqueSizes[$size['size_description']]))
@continue
@endif
{{ $size['size_description'] }}
{{ ($loop->last ? '' : ',') }}
<?php
$uniqueSizes[$size['size_description']] = true;
?>
@endforeach
@endforeach
</strong>
</td>
<td></td>
</tr>
<tr>
<td>
<strong>
Colors:
@foreach ($item['color_size_grid'] as $color => $sizes)
{{ $color }}:
@foreach ($sizes as $size)
{{ $size['size_description'] }}
{{ ($loop->last ? '' : ',') }}
@endforeach
@endforeach
</strong>
</td>
<td></td>
</tr>
</table>
</div>
</div>
@endforeach