How to convert mp4 to GIF ?

[july]

i made an artwork for steam on sony vegas pro and render it as 506x928 30 fps and the file size 6.7mb but when i convert it to GIF in Media Encoder CC 2019 but the file size went from 6.7mb to 49 mb.How do i make it smaller without losing quality ? (im not good with media encoder and after effect i just got into it)