Animated GIF from Animate

Animate can export Animated GIFs and I have produced an animation and want to do just that. The quality, however, is appalling! I have created an artwork in InDesign which is a four page document, each page representing a frame. Usually I export the pages as a PDF and import it into Photoshop, ending up with a four-layer PSD file. From that, I can use the timeline to create an animation, enabling smooth fade in/out transitions between them. The quality of the images are generally of very good quality once exported as a GIF. However, this time around, I have been asked for a much more complex animation, based upon the same document, only with extra elements fading in and out for the duration of the 'movie'. I had two options - to either create a Photoshop file that would have finished up with a good 20 or so layers which would be an absolute headache in terms of adjusting opacity levels of multiple layers per frame, or work it in Animate which offers far easier and time-effective creation of the same finished item. Having created the animation, I have exported it as an Animated GIF. Annoyingly, after spending much time creating it, the images are of really REALLY poor quality. I know that GIFs have a limited colour palette, but compared to the original Photoshop version, they are in a different league! I've been directed to look at the Publish Settings from the File menu to adjust GIF settings. However, there are only options for Javacript/HTML, JPEG, OAM and SVG formats. Before I rip my hair out over this, can anyone help? I have the full CC package so if there is any other software that would be able to assist, I'm all ears. Thank you in advance.