If you want to sync via VPN without any issue about security and speed also than you need VPN that doesn’t compromise your speed. There are many VPN providers available in the market but mostly VPN can completely work for security but they will compromise the speed. I will refer you to use ExpressVPN which keeps your identity anonymous and also don't compromise your internet. I would recommend you giving it a try and in case of you get any inconvenience, you will have a 30-day money back guarantee. If still, you are confused about VPN than here you get the guide about China VPN. It would help you choose which VPN you have to pick in China.