Photoshop animations, too low res for social platforms?


New Member

Im running into a problem, whenever I create a frame animation on Photoshop and export/save for web as legacy, 256 colours,
when I then upload to social media platforms on Instagram it always says too low quality and Facebook it doesn’t look as crisp as it did before I uploaded it.
I’m not sure what I’m doing wrong, please can I check size (I use 1080 x 1080) and PPI people use for social animated videos and how is best to save without them becoming low quality? Do I need to render as video instead? Am I missing something crucial out when creating animated videos?
Thank you in advance!