[Tero Ahlfors]

What are you exporting with what specs? What’s the resolution of the PNG? What are your sequence settings?

[Tero Ahlfors]

Uncompressed(or slightly compressed) image sequences like EXR/DPX/TIFF require a pretty fast storage even in HD.

[Tero Ahlfors]

https://www.nvidia.com/object/adobe-premiere-pro-cc.html

[Tero Ahlfors]

[Jason Jammer] “Any other advice will be greatly appreciated.”

Are you using GPU acceleration? What if you turn that off and export?

[Tero Ahlfors]

The speed will show up after the clip name on the timeline.

[Tero Ahlfors]

If you select the playhead the playback will stop. So, yes, you’ll have to start the playback again after moving the playhead.

If this is a feature you would like to request then go here: https://www.adobe.com/products/wishform.html

[Tero Ahlfors]

There is no export formats in Premiere that can output those framerates.

[Tero Ahlfors]

That feature is not in Premiere.

[Tero Ahlfors]

You need to select some keyframes to have them show up in the graph editor.

[Tero Ahlfors]

https://helpx.adobe.com/after-effects/using/animating-text.html#animate_text_with_text_animators