A couple of WordPress 6.5 release blockers surfaced, one related to the Font Library and the other related to Synced Pattern Overrides. Here is a discussion of the issues, together with the decisions. The short version is that the Font Library will be included in 6.5 and Synced Pattern Overrides will be pushed to 6.6.
Beyond these two issues, the discussion brings to light future plans for block themes. There are plans for “composability” for block themes. From Wikipedia: “Composability is a system design principle that deals with the inter-relationships of components. A highly composable system provides components that can be selected and assembled in various combinations to satisfy specific user requirements.” The news here is that the plan is to allow block themes to be split into components and allow users to swap components (such as fonts) without changing themes.