Support for OAuth Server-to-Server will be supported in the next UST release (v2.9.0). We hope to roll the update into a new release candidate soon.
In the meantime, nothing will break with JWT auth in the near term.
As per the official documentation, all JWT integrations will continue to work until 1 January 2025. In addition, the console will continue to support the creation of new JWT integrations until about a year from now (1 May 2024).