https://www.collaboraonline.com/collabora-office/
Works like a charme across major platforms and formats.

Last time I checked versions for Android and Linux were unpaid.

I have used reveal.js and presenterm for simple work presentations and I enjoyed working with both. You’ll get a lot more flexibility and features from reveal, but presenterm is neat for certain kinds of presentations too.

https://www.onlyoffice.com/ may be an option. They have hosted plans but you can just use the office suite with local files for free if you don't need a yof the hosted offerings features

LaTeX with Beamer for slides, and show the resulting PDF on any computer you want

Marp works well if you like Markdown. I cannot, however, speak to things such as transitions (though marp exports to a nice HTML file which includes a PowerPoint-like interface, so I’d imagine it’s possible).

A long time ago I did some things with https://revealjs.com/ but not sure how viable that is.

Pandoc with reveal.js is nice. I also use an asciidoc template with asciidoctor-pdf, but it's a pdf output so no fancy animations or transitions.

I have a couple write ups about them:

• http://readbeanicecream.surge.sh/2025/02/15/easy-decks-with-pandoc/

• http://readbeanicecream.surge.sh/2025/02/26/quick-decks-with-asciidoctor/

Personally, I'd just use one of the many good markdown / JS presentation frameworks (reveal.js et. al.) out there, a local HTTP server and a browser.

Typst. Quarto. Xaringan. There's lots of good tools.