Exporting Transparent Gif File but edges pixelate

When i am export transparent gif its edges pixelate not same like as in video file what actually issue is

Thats because gif gets compressed and the quality compromises. No solutions except using a different format.

Try exporting a video file from AE (lossless) then importing to Photoshop and the Save for Web (legacy) will let you export a GIF and adjust quality settings till it matches your needs.