jpg and png pixelated on export

When doing anything in Animate that is mainly to export to video, you can do a few things to help improve the quality:

In the library, select all bitmaps and click the i button. Set them all to be lossless, allow smoothing.

In publish settings, Flash, set both audio event and stream to Raw, 44kHz.

Make sure you are using an ActionScript 3.0 FLA, and in the Actions panel, after selecting any layer in frame 1, add this script:

stage.quality = "16x16";

The only other thing that seems odd is your stage size. I think the above things will make the quality be better, but you might set a more typical stage size. I'm just worried that an 1100x400 stage will be processed via a 1280x720 preset. Good chance I'm wrong to worry, so first see if my other tips help.