Female Betta started chasing after my platy & tetra

I feed her a few bloodworms she started chasing after them she never did this before she’s always to herself a few moments after my platy did this weird jerking movement twice he never did before.

 

Bettas can become aggressive at the flick of a switch, and for any reason. She could be worried that they're going to steal her food.
I'm not totally sure about the jerking from the platy, it might be flashing, but I'm not sure.

 

Platy: Fish can kinda jurk when they swallow larger things. If you fed freeze dried, which I don't recommend (Frozen and live and best) and didn't soak them I water first they are dry and a bit harder to swallow.

Betta: Betta aditude can change very very fast. Even females are capable of severely injuring and even killing other fish. Since she is showing aggression, I would separate her asap or she could end up killing her tank mates.

 

I’ve separated her & moved plants & decorations how long do I have to separate her? Because I don’t have a temporary tank at the moment

 

If she's being aggressive, you might not be able to put her back in there. if you can get a different tank, that's the best option, otherwise, rehoming her might be the best option.
You could try putting her back in and watching her to see how she reacts. But, if she goes after the other fish again, I'd separate them permanently