And no, a VPN is not an option (because China is already known to bork unsanctioned VPNs and other encrypted connections)?
They try, but the number of Chinese students here in the UK running VPNs for their friends back home would suggest that they're ineffective in cracking down on them. From my colleges who travel it seems that something like your employers corporate VPN will work, even if say nordVPN is blocked. Not that this is a reliable bias for demonstrating your product if it requires a connection to your server at home, but if you're selling to anyone government owned in China you may well find there's a requirement to host your service locally anyway.