I’d add clear quality options and support for common post formats. When comparing tools,
SnapTik is one you can look at to see what features are currently available. I started using it when I wanted a simple way to keep some Instagram videos for later. What I like is that the process feels straightforward from beginning to end. I copy the video link, paste it, and follow the available download option. I think a good downloader should also make the main action obvious instead of filling the page with unnecessary buttons.