That’s what the feature request WhiteNoise linked to is asking for. To show your support for it you can comment on it or press the heart button under the main post.
Install and use tools like “Delay Start”, “Lingon X”, or “LaunchControl” to configure a delayed launch of Obsidian. These apps allow you to set conditional startup parameters—such as waiting until specific disks are mounted—so that Obsidian doesn’t start before your vault location is available.