MacBook Pro M3 Multiple External Displays

I have two 4k monitors and an M3 MacBook Pro. I was shocked to find out that getting these two monitors to work with my Mac is no easy task. I have an HP G5 dock with a USB-C connection. Both of my monitors are connected to this dock via display port cables. Currently, when I plug the dock into my laptop, I keep my laptop screen as a display, and then both monitors turn on as a second display, but mirror each other. So 3 screens are on but I only actually have 2 displays.

I'm aware that there is a limit of 2 separate displays that can be extended onto - I only want 2, but I just want them both to be my monitors, and my Mac itself can be closed.

I have seen on some older threads here that people have managed to achieve this with the HP G5 dock but it doesn't seem to be working for me. I've also tried connecting one monitor to the HDMI port on my laptop directly but this turns off the other monitor, and when I close my laptop everything turns off rather than display on the monitors instead. I've also tried connecting each monitor to a USB-C port on the laptop (using two USB-C to HDMI adapters) but only to the same effect. I also tried using some display manager apps to see if I could set the monitors as separate displays rather than mirrored but again no luck.

Any help/suggestions appreciated. Not sure why this is so difficult. For reference, I'm running Sonoma 14.1.

Thanks.