Best app for live presentation with annotation

I wanted to give a class lecture by annotating a presentation live, working out examples, going through the math, etc. What’s the best app for doing so?
Notability only works with PDFs which means any animations are lost, and jumping from page to page uses a continuous scrolling animation. It’s fairly quick, but I’d prefer instant transition so that I can kinda mock “appear” animations.
PPT for iOS lets you draw on the slides, but the pen tool is pretty rudimentary (comparatively).
I’ve heard keynote also allows annotation, but how does it compare to PPT? and how well does it handle .pptx files?
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