If you haven't already, I'd suggest you read this document carefully: https://documentation.meraki.com/MX/Site-to-site_VPN/China_Auto_VPN
Also this one, at a higher level: https://documentation.meraki.com/General_Administration/Support/Information_for_Users_in_China
Basically, in China you are recommended to deploy Meraki devices into an Organization within the China cloud. Doing this precludes forming AutoVPN (SD-WAN) tunnels to an MX in a different Organization, of course.
If you choose not to follow the recommendation and physically deploy an MX in China, but as part of a non-China Org, while you may or may not get VPN to come up, to other locations, there would be no guarantees around whether it would stay working, nor around its performance .