My cat hates my housemates cats

Hi,

I recently moved in with a new housemate who has two cats and my younger cat hates them.
I have 2 cats, one is 3 years old (Mew) and the other is 11 months (Pichu).

As some backstory, she was adopted young and has always liked her older brother and had no problem when we first introduced on another.
When we moved to the new house I thought things would be okay if we did slow introductions (let them see each other through a barrier and as time progressed remove the barrier). We did some scent swapping, playing by the door, feeding by the door, letting my older cat go out (he has no issue with any of the cats)

We did the barrier for about three weeks and she was fine at first but one of my housemates cats swung at her once without any hissing and since then she’s been terrified of them. She hisses and growls any time one of them is within 3 feet of her. We experimented with adding and removing line of sight from each other and doing more scent swaps but we are still at square one. It has been about 3 months and we let her out of the room a bit to see if maybe she just needed to get out but one of my housemates cats had some obsession with her and keeps trying to get closer despite her constant distress.

This has been super cyclical and it feels like we will never make progress. I left out some detail for the sake of brevity but Id appreciate if anyone could pitch in on how to make this work better. She gets scared and anxious easy which makes this all the more difficult.

Thanks.