They are all communists: China, Vietnam and North Korea, and will remain so. They are myopic and intransigent. Deal with them at arm’s length.
The two biggest problems are China wants and how deal with the DPRK government. China wants regional military influence and global economic power. The DPRK governments wants security guarantees. Which means they to have political power in a unified Korea and not be held accountable for every dirty thing they've done over the last 70 years.