How and when to give input about a fellow clerk on probation?

I'm not one who enjoys drama and have held my tongue a lot, but if this person ends up passing probation, I may genuinely consider leaving. This is in distro, so we often work overnights with no supervision.

They tried to make a bunch of changes right after starting, and they wouldn't take no for an answer. They specifically tried to do this when our most senior clerk was on vacation.

They get defensive as soon as you give them constructive suggestions or even just new information.

They talk shit about our senior clerk when that person isn't scheduled and tries to coax our youngest coworker into joining in on it.

They are still so slow, throwing two small parcels at a time and rarely going for bigger boxes. I know speed doesn't matter, but it literally is to the point where it's slowing the rest of us down too. We just want to be able to go home on time, and we have to work doubletime to do that now.

I also feel like there's some misogyny going on...our former clerks would be crass or have shop talk or whatever, but this feels different. I'm not sure how much detail to go into, but it's more like subtle animosity and superiority rather than just crassness.

My senior coworker says to talk to the station manager, at LEAST so there is a record of the instances that made me feel unsafe around them, but. I don't know how that would pan out, and I fear it coming back on ME.

Whew, sorry for the rant. Tldr: How to tell station manager about coworker who is snide, arrogant, impeding our work, and subtly but persistently sexist without it just being a case of stirring the pot?