This sort of thing is a known historical attack surface. At one point not too long ago, people were attacking Discord's browser and desktop clients by embedding massive carefully-authored GIF files to exploit the fact that Chromium (thus, Chrome and Electron) decodes GIFs partially or wholly in advance, so the GIF would quickly consume all memory available to the tab/app and either crash it or bog down the system.

I think Discord implemented some measures to guard against those files and Chromium was patched to mitigate this (which is why Edge and Vivaldi are fine), so it's not surprising that something like Safari might struggle with Evil GIFs under certain circumstances as well.