On the AWS side have you tried a "Transit Gateway" in place of the "Virtual Private Gateway" ?   My reading of Transit Gateways is that it acts like a router inside AWS to connect multiple VPCs together and provide a single "public" interface.  They do cost money though, slightly more than the VPN (in my region), so would be about double your current cost as you still need to pay for the VPN.       Though may not get around the 1 subnet limit on the Meraki side unless all VPCs in the Transit Gateway map into a single CIDR. ... View more