Basically the person stays in their spot when you leave them on a video call so, I believe it's 안녕히 계세요.

안녕이 가세요 & 안녕이계세요

How do you use them when you leave a videocall or a chat?

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If you leaving, you can say 안녕히 계세요.

If someone leaving from you, you can say 안녕히 가세요.