Hi @Dami1,
Thank you for your question and welcome to the Bunnings Workshop community, it is fantastic to have you join us.
I hate to be the bearer of bad news, but you're going to have to remove the render and start over.
This amount of cracking, even if it is superficial, indicates the render is moving. This is likely because it has lost adhesion to the surface beneath. If you were to simply fill the cracks, or render over the existing render, the cracks would reappear because the render is not adequately attached to the surface beneath.
I'd suggest using a Kango 150mm Joint Knife to remove the existing render and return it to a bare surface. Please note that there are external angles similar to these Siniat PVC External Render Trims on the corners, be careful not to damage these when removing the render as they are likely reusable.
Once you are back to a bare surface, you can use a render such as Dunlop 20kg Multipurpose Acrylic Render to replace the render you've removed.
You might like to check out How To Render for some guidance on this process.
The gap filler will also need to be removed and replaced. This can be done with a utility knife, but please be careful and wear gloves and a long-sleeved work shirt to reduce the risk of lacerations.
Once removed, it can be replaced with an external gap filler such as Selleys No More Gaps Exterior Gap Filler.
You might like to check out How To Silicone a Gap for some guidance on this process.
Let me know if you have any further questions, or require further assistance.
Jacob
