First off deco M4 only has gig Ethernet ports so the maximum speed you could get from wired is between 940-960Mbps.
The wireless spec is AC1200
5 GHz: 867 Mbps (802.11ac)
2.4 GHz: 300 Mbps (802.11n)
these are maximum speeds however and based on past experience with AC1200 /wifi5 400 - 500 Mbps would likely be the maximum throughput you would get.
I’ve got the newer X50 which is AX3000/Wi-Fi6. The 5 GHz band is quoted as running at 2400Mbps - in reality I get about 650 Mbps when stood next to the unit, and 300 Mbps when connected via one of the satellite units. I do live in an area which is heavily congested with other Wi-Fi signals though .