Watching the Cycling on Discovery+ on Fire stick vs Ipad/Android phone

Just wondered if anybody knows whether it’s the Discovery+ app on the fire stick or the fire stick itself that makes loading it and running it such a slow and clumpy experience as opposed to the slick experience on the iPad or my Android phone?

I have no problems with the fire stick runs the same as it does on my Apple TV is your internet connection good …?

50-60 Meg. Everything else runs ok on the stick and simultaneously on the various phones & iPads in the house.