Copied over from the Resolve forum:
Peter Chamberlain wrote:UIManager based scripts and workflows need DaVinci Resolve Studio or Fusion Studio to be accessible.
For some time scripting through any UI has been the domain of the Studio version - this includes node.js based and UIManager based scripts and Workflow Integrations. Some workflows slipped through earlier versions and its taken some time to get to this but in Resolve 19.1, we addressed this issue with UIManager to be consistent with Workflow Integrations.
Of particular note:
Reactor is now no longer operable in the free version of Resolve. So we're all going to have to remind ourselves where to put macros, scripts, and fuses.