@jacky1mcc-
The Hulu app on my several different Rokus has no provisions that I can find for altering the playback speed.
This really would be a question for Hulu, as they provide and maintain the Roku-compatible version of their channel app to Roku. Roku only provides the platform on which it is being run.
Roku Community Streaming Expert
I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well.
If this post solves your problem please help others find this answer by clicking "Accept as Solution.".
Ultra 4800 | Streaming Stick 4K+ 3821 | TCL Roku TV 43S245/C107X