May I know the most affordable and safest way to get from Guangzhou Airport to Sofitel Hotel at 2am?

I suggest you take shuttle bus line 6A to CITIC Plaza first. It takes around 50min and costs CNY20. The shuttle bus operates till the arrival of the last flight. Then you may take a taxi to reach the hotel directly for a distance of no more than 1.2mi, which costs CNY10.