I always liked (and still use) GIF Brewery, which eventually hooked up with Gyfcat, and is now relegated to being parked at softonic (never feel like these are safe to download). Gives a lot of control over the final file. Here's a 800px wide, 10fps, 24color version that's 5.5MB.
GIF Brewery was one of the reasons I built this, I could never quite get the output I wanted and the process was never very intuitive to me. Not to mention its future being unclear
I've played around with gifsicle, which is awesome, but can't seem to replicate the quality for the size. With your source (and lots of chatgpt), I did eventually get a similar output that's pretty close to the size from Gif Brewery – 6.7MB vs 5.5MB. I'll definitely keep playing with it.
