While I do work for Meraki, I have no specific answer to this, at this time - but I would take a look at the kind of performance available from the likes of MX67/68, within the MX Sizing Guide - and wonder whether you could actually gain anything from the extra bandwidth that WiFi6 might offer..? If it were me, I'd be choosing my MX and my preferred MR access point separately. This also allows you to put the AP in the best place for coverage, leaving your MX safely in a rack or similar - plus you could deploy more than one AP, to have a fully roaming WLAN, should you need to extend your coverage.