FYI, big messages like this can be made more channel-friendly by 1) Putting them in threads, below a shorter intro message, and 2) Using text snippets, so they become collapsible (and can be syntax highlighted, which is helpful too).

Generally, Pulumi tries to create replacements before deleting the original. This is helpful most of the time, to ensure continuity of service, security, etc. (removing an SG from your prod server before adding the new one could be risky). But sometimes the provider won't allow two similar things exist at the same time (as in this case), so you have to tell Pulumi to delete the old one before creating the new one.