My child (age 5) keeps getting frustrated with their sibling (age 2) and grabbing their head and shaking it.

I have tried a few different methods but so far nothing has worked. My youngest is not innocent, they are doing things to piss the 5 yr old off. But they are 2 and I can’t keep them separate all day.

How would you discipline this?

And before you suggest spanking, I am 5ft and pregnant. 5 year old is getting too strong and I see strapping them down as abusive and possibly phobia inducing. I also avoid spankings as much as possible.