Theoretically, if you advertise this network in the site-to-site VPN configuration, you do not need to add statistical routes.
The only case that saw this need was when using Linux.
Is this VPN network enabled to participate in SD-WAN? Can you send a printscreen of the configuration?
I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.
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