Art is being stifled over here smh

583MB is actually the best amount of MB to have.

Don't stop the signal! I use https://ezgif.com/video-to-gif as a really quick and dirty way to resize and reduce quality and file size.

Host your images somewhere else. I've been sing imgbb. Back in the day anytime I ran out of space on geocities I would just register a new account. Alternatively I think you could get away with using archive.org to host images for free. I use archive.org to host a ton of mp3 files for my purposes.

If you want an offline option for GIF optimisation (might be hard to do since it's footage), I recommend gifsicle. For editing the video before turning it into a GIF (like reducing the frame rate or something else) ffmpeg can do that (also offline). Also as jerryscoolpage mentioned, you can host videos on another platform and link to them (YouTube, PeerTube, somewhere else)

Thanks for suggestions everyone! I'm hesitant to host elsewhere since I don't want to run into issues if the image hosting platform goes down or changes hotlinking policies, but I'lll see what options are available if it comes to that. I actually use ezgif already @p7uen!