I can only sympathise, it is heartbreaking to see your hard work and money being destroyed.
A high fence, (different heights for different deer) really is the only solution. We are fortunate that we only have a roe deer problem, so the fence is only 5 - 6 feet high. Also, you have to have it down close to the ground, they can crawl under surprisingly small spaces, and they will find the space if it exists!
Have tried a few shop bought products, i.e. Lion dung, Human hair, Products which are systemic to plants to alter the taste, but nothing worked.

I agree. In this part of the world, deer are a real problem and high fencing is really the only answer. If it is wire, it needs to be tagged here and there with marker tapes, so that it becomes 'visible' to the animals.