After attending a conference presenting OpenRewrite (see links below), I tested the No Guava recipe on the Sirius-Desktop codebase.
The NoGuava recipe does not yet allow replacing all Guava usages. I fixed some several issues in the recipe or opened new issues, which were later addressed by the OpenRewrite team. With the latest version available at the time of my analysis (3.19.0), the results improved significantly, though not fully: 179 compilation errors remaining, compared to 437 at the start.
A synthesis has been written on OpenRewrite repository (issue #928).
This issue is meant to keep a trace on the Sirius side. I will also push the branch I used for my tests.