Coupang is going to go IPO by 2020 or sooner. Take into account the stocks you are getting and model with different target prices to figure out your TC. Look at JD for comparison. Coupangs cash offer is usually lower precisely for this reason. The value is in the pre-ipo stock, work and growth potential.
Look at yoy revenue growth. No public valuation means stocks were not diluted. Revenue growth over last 3 years points to increase in stock value. Look at public company in the region with same business model (JD.com). What should trump everything else is wether you think you like the work.