You're not being negative enough when it comes to non-Android linux phones, and even when it comes to Android, there's just ONE serious project - GrapheneOS which has people working full-time and which will be officially supported on future Motorola flagships.
Unfortunately even that one is missing modern replacements of outdated unsupported AOSP sample apps (like Phone and Contacts, others can be replaced without extra privileges).
AOSP is quickly becoming a dead end as Google tightens its grip on Android.
calyx os seems serious?
Doesn't LineageOS have modern versions of those things?
I'm not sure it has to have money involved to be serious, and in fact the last time Lineage had money involved it didn't end very well.