Oppo has published a global timeline of updating existing models to ColorOS 13 (Android 13) for the first three months of the new year. This is similar to the Chinese timeline, but with more precise timing in some regions.
The update process will take some time. For example, Oppo started updating its Find X5 and older Find X3 series in December, and the rollout is still in progress. Users are already running ColorOS 13 and others are still waiting for the update.

Anyway, Q1 plans also include several generations of the Reno series.
Some phones are moving from beta to stable release. The Oppo Find X2 and X2 Pro were still in beta row in December, but will start stable release in select regions from January 13th. Please note that in other regions, the X2 and X2 Pro updates still need work and remain in beta for now.
Here are links to all phones getting stable ColorOS 13/Android 13 in January.
in progress
From January 13th
From January 14th