If you've tried everything, you already know the cycle. Spray something. Light a candle. Shampoo the carpet. It smells better for a few hours. Maybe a day. Then it creeps back.
The reason nothing sticks is that you've been cleaning surfaces while the problem is in the air.
Tiny odour-causing particles become airborne and circulate through your home continuously — rising from carpets, couches, cushions, and pet bedding.
Even when surfaces look spotless, the air is still carrying the smell.
And masking products actually make it worse — a living room that smells like "lavender plus dog" isn't fooling anyone. It draws more attention to the problem.