I have successfully installed Waydroid on a x86_64 device and linux-7.1.5-arch1-2 has the necessary kernel modules.
On my RPi 5, using the Archlinux ARM latest kernel linux-rpi-16k-6.18.39-x Waydroid did not work. I assume the older 6.18.39-x kernel did not have the needed kernel modules.
When i get a moment, I am going to install your linux-rpi-16k-7.1.5 and see if it works.