Apple did not tell me that front camera is non repairable at time of purchase of my iPhone X

There are only 2 things that are repairable on an iPhone; a battery replacement and a screen replacement. There is nothing else that is repairable. For any other failure out of warranty Apple replaces the phone for a fixed fee and sends the phone to a central repair facility where the failure is analyzed and the phone either refurbished or recycled, depending on the nature of the failure.

It is not cost effective to do field repairs, considering the training and the cost of labor in most countries.