Making high quality GIF from video in Ubuntu 20.04LTS

First install gif.ski using snap.

snap install gifski;

Then use ffmpeg to break down your video to frames:

ffmpeg -i video.mp4 frame%05d.png;

Finally use gif.ski to create your gif from the frames:

gifski -o clip.gif frame*.png;

Delete the frames if you do not need them, they will be taking a lot of space.