@DanielBenden your Meraki partner should be able to provide an indication of the lead times for products, it’s available to them through the Meraki Partner Portal, and it depends on the product and the region you are in.
If you know items are going to take a long time then splitting the order (I.e. making two separate orders - Cisco Meraki won’t split them) will generally mean you get the available parts quicker.
My experience has been that the MR36 have a long lead time, and also the MX67C (if it’s the WW version) - using a MX67 with a MG21 has been quicker to get (and in my mind more flexible, but it depends what you are trying to achieve).
Hope this helps.