<p>I'd like some advice regarding defects on my print :
<a href="https://i.stack.imgur.com/5x4u2.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/5x4u2.jpg" alt="enter image description here"></a></p>

<p><a href="https://i.stack.imgur.com/3CgUe.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/3CgUe.jpg" alt="enter image description here"></a></p>

<p>Here some details :</p>

<ul>
<li>Printer CR-10 S, nozzle 0.4</li>
<li>Material PLA</li>
<li>Bed 60, Hotend 215, 50 mm/s speed</li>
<li>SLiced with cura 4.1, 5 walls (i can provide more detail of the profile if needed)</li>
<li>Layer height 0.1</li>
<li>modeled on fusion 360</li>
<li>The surface where the defect sits is actually tilted 45 degres</li>
</ul>

<p>Thanks !</p>

If you break up a large piece into multiple smaller pieces and properly glue them together, you basically add stiffeners (as a result of printing walls). This could lead to a more stiff model; this might have been confused by calling large prints more brittle opposed to constructed models.
If printing is conducted at similar conditions on large printers, there shouldn't be a reason why the model becomes more brittle unless the conditions aren't the same. But that would be true for printing at small printers too, e.g. if one print was printed in a draft.