This problem was driving me up a wall, but the keybinding posted on that issue fixes it for me https://github.com/zed-industries/zed/issues/37190
`cmd-shift-right` does not select the last character in Vim mode · Issue #37190 · zed-industries/zed

Summary On macOS, ⌘⇧→, which is mapped to ["editor::SelectToEndOfLine", { "stop_at_soft_wraps": true }], does not select the last character of the line when Vim mode is enabled and in normal mode. ...

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