UK Replacing 1 gang 2 way switch with smart switch

I have a fairly typical setup of the light on my landing being able to be controlled by both a switch on the landing and a switch at the bottom of the stairs. I'm aiming to replace the 1 gang switch on the landing with a smart one (I've bought the Aqara H1 single rocker with neutral), with a likely plan to replace the one downstairs too (once I find a three-gang smart switch I like).

The way I have my house set up is that I have smart bulbs in most locations, including on the landing, so I usually have these switches set to decoupled mode, where the light will always stay powered, but pressing the switch will send a command to my hub to instruct the bulb to toggle on/off. In rooms with only single switches in place, I can then go into the app to kill power to the bulb only when I need to replace the bulb. In this instance I'm fine to just leave the light circuit permanently powered at this point if that works best, given the standard switch at the bottom of the stairs, but I'm also fine to just remove any connection to that downstairs switch and revert the upstairs one to a 1 way solution too.

The confusion I'm hitting as I'm doing research on this online is that when I compare diagrams such as the one here, I seem to have too many cables in my wall, they don't seem to be in the same configuration as the online diagram, and I am struggling to figure out what's what. Excluding the ground and neutral wires, that diagram has 5 wires connected to the first switch, whereas I seem to have 6.

My current wiring is that I have a brown wire going into the COM port, a grey and a brown wire going into the 1WAY port and a black wire going into the 2WAY port, all coming from the same opening in the back box. From the other opening, I have two brown wires going into the 2WAY port, and two blue wires (I believe neutral) that just go into a connector block.

The smart switch I'm hoping to put in place here has only three connection ports - Neutral, Live and L1.

Given the neutral wires are coming from the one side, I'm assuming that that's the side that goes up to the light itself, and the two brown wires are the live and the switched live wires, though why they're both going into the same port on the faceplate confuses me. Am I right in thinking that if I can figure out which is which between those two brown wires, I should be able to just terminate the other four wires into connector blocks to cut the connection with the downstairs switch, and wire it up like a normal switch? Is there some other way that I can wire in this smart switch?

I've attached a photo of the connections on the back of the faceplate, a diagram of where the wires look to be going, and also a quick diagram showing the light switch setup I have in my hallway/landing.

My house is a relatively new build (around 2018), so modern wiring colours should match up, but also sometimes wiring is weird in new homes I've found.