The community server does already allow use of another server implementing the solid-oidc flow, e.g. through the setup screens.
However it’s worth noting that solid-oidc is an extension of oidc, so what you’re asking is rather advanced and requires detailed understanding of the solid-oidc spec (as well as, e.g. Google’s own requirements).
You might also find this thread useful: Login to a SOLID Pod from a Flutter app - #8 by zwifi