Hello darlings,
I managed to use "Passthrough Mode", I did a test here with an MX68 and 2 switches... 02 mode trunk interfaces, and it worked... the topology looked like this:
[Internet] -- [Fw-Edge] -- int trunk --> [Wan MERAKI_MX68 Lan] <-- int trunk --> [Switch2960-X] <--- [Access_port Notebook Client_Test].
I configured the trunk interfaces with 03 VLANs, I placed the Meraki in the middle between my access switch and the distribution switch and everything works. The only detail that I didn't find in any document is that you need to "set" the VLAN ID on the Meraki WAN interface, so it needs to know which VLAN of this trunk it will use to get the IP and register with the Meraki connector. After that I get a normal IP on 3 different Vlans on my access switch where my notebook is connected. Meraki worked perfectly in the middle between LAN and WAN, monitoring the network/clients. Thank you all for your help.