> while Outlook supports starting five minutes late

This contrast is an incorrect assumption. Outlook does allow starting meetings late as well as ending meetings early, with somewhat arbitrary durations. [1] I have definitely seen these options in Outlook settings (on web, since I hate Outlook).

However, I haven’t used it because the teams one works with need to be alerted and reminded of it before it sticks in their minds (if nobody else is using such settings).

[1]: https://support.microsoft.com/en-us/office/end-meetings-earl...