Jumping on an older thread here, but we tried this setting in our organization (monthly enterprise channel / M365 E3) to no avail. I did notice on an old, licensed testing account I have that the setting actually did work and the meetings were shortened. None of our users we have checked with saw a change though, whether their mailbox was migrated from on-prem or it was created in Exchange Online. Logged a ticket with O365 support. After some testing and research on their end they said the organizational setting would only apply to new users who are created after the setting was changed, or existing users who have never had any calendar appointment created on their calendar. The latter was the case for the testing account. It was an existing user prior to the org-wide setting change that had never had a calendar appointment and the setting worked. They are giving me reg. values to deploy via GPO to affect the Outlook desktop app which is not at all the same thing. Two-thirds of our users are frontline and only use the mobile or web app.
Gabriel_Valdez - Is that the intended affect of the organizational setting? That it only applies to NEW users in the tenant? The 2nd bullet point in your original post makes it seem like it would apply to "everyone at a company".