Agreed, halium and Ubuntu Touch aren’t true Linux phones in my book. To be a true Linux phone you need to run mainline, or at least very close to it (pmOS forks, Megi kernel, etc) and do things the Linux way not the Android way (KMS/DRM/Mesa stack, ALSA/Pulse/Pipewire stack). There are some phones that are getting there thanks to postmarketOS like the OnePlus 6/6T but the ones you listed are the main true Linux phones.
Typing this from my PinePhone Pro running postmarketOS.