As discussed in the linked forum post, the ODATA filters for Start & End Date/Time are being ignored. Not sure if being ignored by the Flow connector or the Outlook API.
https://powerusers.microsoft.com/t5/Flow-Forum/How-to-get-last-two-weeks-of-data/td-p/16481
@v-micsh-msft recommended I submit the bug as an idea.
This is now possible with the Get Calendar View action: https://flow.microsoft.com/blog/publishing-and-custom-connectors/