I’m a user of Impress, and I have a bunch of friends that have settled on it for their presentations, too.
We are generally happy, but for the video side. When you insert a video in your presentation, there is no way to pause and rewind, look for a point of the video. It is a known issue, open for 10 years, and we were wondering if there is a fundamental reason or obstacle for this feature.
Who knows? Have you tried OnlyOffice?
I did, last time two months ago. Unfortunately their presentation software is pretty minimal at the moment, and I prefer the fully open ODP standard. Anyways, at the time there was an issue with videos that weren’t playing at all.