If you don’t mind clutter free, simple presentations, try hack.md or cryptpad. Both supports markdown styled presentations, both are FOSS cloud applications and the format of the presentation is highly portable.
If you want to get really ambitious, try marp framework for presentations - still markdown but on steroids.
Hmm, nocodb is a webapp first and foremost. It does have binaries to run directly on the host, but I’m not entirely sure to recommend this over libreoffice actual app for database management. I believe it would be more in line with OPs requirement.