If the oven has a self-cleaning mode, seems all modern ovens have that, then DO NOT use normal cleaning products inside it.

It then has a special covering on the inside, which burns fat with high temperatures. Normal cleaning products can kill that covering, so you will have to replace the inside of the oven.

Happened to my ex-wife when she moved out.
The people she hired to clean the appartment seemingly did that, but she was not there and they denied it.
Anyway, think it cost her like 700 francs if I remember correctly.