CalyxOS seems to support some motarola phones and two fair phones https://calyxos.org/docs/guide/device-support/. LineageOS seems to support a wide array of devices (including some from the Chinese brand Xiaomi) https://wiki.lineageos.org/devices/. However GrapheneOS only supports pixels https://grapheneos.org/faq. You could always just buy a pixel second hand if you don't want to support google. WeChat should work on all of these ROM's as they are just modified android.

That's not the only way, you could install a de-googled android ROM like LineageOS, CalyxOS or GrapheneOS.