How import PPT/PPTX slides with annotations/ink into Impress?

Google has failed me on this, as has the docs. And I thought this worked with an earlier version of Libreoffice (e.g. 6.3.3 vs In any case …

What I have are slidedecks in MS Powerpoint format (PPT/PPTX) and many of them have “ink” or stylus-created annotations that were made during the original presentation of the slides. I would like to pull these into LibreOffice to re-edit and re-present, in some cases with the annotations already in place.

I can go through the laborious task of uploading to Google Slides and then downloading. That seems like it should be unnecessary though.

Can anyone tell me the correct settings or extension or rain-dance to do in order to import the Powerpoint slides into Libreoffice while maintaining the annotations?

Additional info: Apologies for not putting down what environment I am dealing with. It is Linux Mint 19.3 (Ubuntu 18.04) and the version of LO I was wanting to use is More fully:

Kernel: 4.15.0-76-generic x86_64 bits: 64 compiler: gcc
v: 7.4.0 Desktop: Cinnamon 4.4.8 wm: muffin dm: LightDM Distro: Linux Mint 19.3 Tricia
base: Ubuntu 18.04 bionic