A driver is a driver, an application is an application. You elaborated on RME drivers, but you quote something about Eventide plugins, which are applications. Driver and application coding are different things, have different technical/coding requirements and need different developer skills.
Incidentally, behind such advertising statements is nothing more than the statement that the application is supported under Sonoma, can be started on the computer and works in principle. But how that then works under load or in interaction with other applications / DAW is another thing. Furthermore, an application cannot fix any Apple problems in the area of memory compression and what not (which led finally to issues).
In the end, Apple seems to have fixed something in Sonoma (so that EDIT: some issues were gone for some people). Eventide says no more and no less in their advertisement that their products run under Sonoma. Additionally, they point out that not all DAWs support Sonoma yet. This hint is most likely meant to prevent any DAW issues from ending up in their support area.
BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14