Your goal is to link two access points (APs) to distinct interfaces without the need for an additional switch. However, you want them to utilize the same IP subnet and DHCP pool. While the concept of an "Aggregate Interface" may not be suitable for this scenario, you might contemplate employing VLANs to segregate AP traffic within the same physical interface, each with its own IP subnet. Alternatively, opting for a managed switch could offer a straightforward solution by guaranteeing appropriate isolation while still preserving network connectivity.

Connecting multiple devices directly to a single network interface without an intermediary switch can lead to issues such as IP conflicts and packet collisions. Devices sharing the same interface may inadvertently use the same IP address, causing connectivity problems. Additionally, without a switch, they lack collision detection and can experience packet collisions, resulting in data corruption and reduced performance. To avoid these issues and ensure efficient network operation, it's advisable to use a network switch when connecting multiple devices to a single interface, as switches provide MAC address learning, collision avoidance, and improved bandwidth allocation.

Kindly do this acitivity with layer 2 or layer 3 switch easy to manage

You're aiming to connect two access points (APs) to separate interfaces without an extra switch, yet have them share the same IP subnet and DHCP pool. While "Aggregate Interface" won't fit here, you could consider using VLANs to separate AP traffic on the same physical interface, each with its IP subnet. Alternatively, a managed switch would provide a straightforward solution by ensuring proper isolation while maintaining network connectivity.

If you use a switch for this, it will be simpler.

Alternately, you may setup a vlan and trunk the ports x4 and x5, allowing both ports to use the same DHCP pool and have the same zone.

Because it wouldn't offer isolation between them, an aggregate interface is not suited for connecting two devices in the same zone.

By establishing a seamless connection between the two access points on the identical DMZ interfaces, we ensure a harmonious integration without any conflicts whatsoever.

It sounds like you want to connect two APs to two separate interfaces on a device while having them operate within the same DMZ zone and share the same IP address range. While this might not be a typical network configuration, you could achieve this by using bridge interfaces.

Connecting the 2 ap on the same DMZ interfaces has no conflict at all

Due to the fact that each device's interface only expects to interact with one MAC address, connecting several devices to a single interface without a switch in between might cause problems like IP conflicts and packet collisions.

In this case, where you want the two APs to share the same IP range and behave as if they are connected to the same interface, link aggregation, also known as an aggregate interface, is often used for load balancing or failover. It may not be the best solution.