What to do with sudden crack on induction hob, landlord and haftpflichtversicherung does not cover it?

Hi, so I suddenly noticed that the induction hob in my flat cracked. There are no impact marks and nothing really fell on it. I just noticed the crack when I wiped it down and the surface seemed uneven.

I informed my landlord of the situation, and asked if maybe the unit was still covered by warranty. Photo 2 shows the full unit. He informed me however that even if there are no impact marks, it should be assumed that it was indeed caused by one and I should instead inquire with my liability insurance.

Called up the my personal liability insurance and was informed that this is considered glass, and glass is excluded from the coverage, I should have gotten a separate Glass insurance (honestly did not know that this was a thing).

Do I have any other options here? What should I do?