This question already has an answer here:

How can we load custom product collection with layered navigation? Same like search result page but with custom product collection. I have checked here Magento 2 - Layered Navigation for Custom Product Collection but still there is no any accepted answer.

marked as duplicate by 7ochem, Jai, Piyush, Keyur Shah, Manashvi Birla Jun 21 '18 at 19:11

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.