Works just fine in X11, but when I switch over to Wayland it only gets detected as a mouse (for all keys) - unable to do much in the way of troubleshooting due to aforementioned issue.
I doubt this is an Akko-specific issue- most keyboards should be using the standard USB HID drivers built into the kernel. This has most likely got something to do with your DE or distro config, maybe an error in a config file somewhere, or some script/plugin behaving funky. I know in the past KDE's Snap Assist plugin was known to cause the keyboard to stop working; kwin scripts could also do weird things. Or could be a third-party program, like a keyboard remapper (kmonad, wayland-mouse-mapper, kbct etc).
You could try switching to a different DE temporarily to rule out a DE issue, but before you do that, maybe boot from a live USB of a different DE or distro (or maybe even try two ISOs of your current distro - one ISO with whatever DE you're using currently, and another ISO with a different DE) and see if it works in there? You could create a Ventoy live USB to make it easy - just dump all the different ISOs on the drive and you can select which them when booting.
If, in your testing, you find that your keyboard works fine with the same distro and DE, then it would point to a config issue. In that case, the easiest fix is to just blow your .config folders away (or create a new user account) and start fresh.
But if in your testing you find that the keyboard works under a different DE but not the one you're using, then it's likely a bug with the DE, so perhaps consider filing a bug report. But maybe try the same DE with a different distro first to make sure it's not a distro-specific bug.