Sorry but I already tried it. They said they need support from head office, but they probably won’t support it because it’s too old.
And that’s right. I will post another post about Fluent usability issues. thank you

For reference, Design Modeler does not work from v17.0 to 2020 R1. Design Modeler works from 2021 R1 onwards.
If you try to open Geometry in Workbench from v17.0 to 2020 R1, it will run as Spaceclaim without exception.