Fairphone's new CEO, Reinier Hendriks, aims to take the company global by making deals with manufacturers to bring down the cost of its ultra-repairable, sustainable phones to as little as €400 in order to compete with giants like Apple, Samsung, and Xiaomi. https://www.notebookcheck.net/Fairphone-5-targets-42-price-cut-in-global-market-push-for-sustainable-smartphone.823522.0.html
Unless it is willing to pour a massive warchest into Marketing, it's highly unlikely it will be able to compete on price alone.
OnePlus 12R was available for $400 after trading in any device, and no dent in anyone's market share.