While not as tight to the blade as a riving knife, I've found these splitters[1] paired with a zero-clearance insert are an excellent alternative, and can be custom-fitted to almost any saw with nothing but a hand drill and the saw itself.

[1] https://www.microjig.com/collections/mj-splitter

I learned respect for my table saw early in my software engineer turned part time woodworker career after a near miss kick back incident. I’ve been using MJ splitters ever since on my old school Delta unisaw.

Neat! I didn't know this existed. A wonderful retro-fit for older saws!