I'm not able to log in to Reddit on Safari on the latest RC.
It works fine on iOS and iPadOS with the very same set of credentials.
On Mac it works with third party browsers (Brave Browser).
I can't log into reddit via Safari either. Says incorrect password even after changing it. Replicated this on 2 Macs. My PC works fine using Chrome, Firefox, and Edge. Also my Macs work fine using Chrome and Firefox.