i took a quick look through the UI, and then the forums.
i use logic’s tempo automation track and rewire to occasionally make music have a bezier tunable tempo. it’s weird and it’s fun…
i was looking to see if this way is maybe convoluted and went looking through renoise’s new features for a way of doing this and came up empty.
in the past I’ve done similar things with the pattern tempo command, but I realized that if this parameter was accessible via a Meta DSP device, it would be fairly easy to automate.
I guess theoretically, you could put certain other global settings (besides tempo) into a meta device like this, like all the commands from the Zxxx section.