The RT2600ac can be operated as an access point behind another router (bridge mode => connection via Ethernet to the router). It can also be integrated into an MR2200ac mesh wireless network but has the disadvantage that it only has a 5GHz WLAN => the dedicated 5GHz WLAN for the connection to the router is not available. The RT2600ac has more memory and slightly more processing power and is therefore better suited as a router than the MR2200ac, i.e. I would use the RT2600ac as a router and the MR2200ac as APs.

I also have 2 MR2200ac and one RT2600ac. However, the RT2600ac is also used as a router behind the SwissCom box to separate the networks.