Any tips to get old textured vinyl clean?

I think that floor has seen better days. I would replace it.

I don't know if you could rent one of these machines but this is pretty awesome: https://www.youtube.com/watch?v=BxFvqcWUnwA

https://www.youtube.com/watch?v=krgLc5IgiiA

You can run new flooring right over top of the old as long as there are no gouges or large damage

If you can't replace it steam it. My mom's house was like that, when we moved back to the same state to take care of her my feet were worse than that - it was appalling. But I have a steam shark and it made a drastic difference. It may take a couple times, and definitely buy extra pads so you can change them out while doing the floors.

I think replacing it is the only option.

If the floor was just dirty, then steam cleaning would be worth the time and effort. However, this floor is so worn out that both the design and colour are almost non existent. It is so porous that it is just going to absorb any dirt like a magnet again after cleaning.

Agree with everyone who said it's time to replace.