This is a job for your and her manager.
It's one of the reasons they're paid more than you are - partly to ensure a harmonious work environment for all.
Having an unofficial little word with her yourself, aonymous notes, mystery cans of deodorant appearing, spraying stuff around are all an absolute no no and could be seen as bullying.
There should be something about this in the staff handbook.
Message your manager in careful terms, quote the handbook section, and make it quite clear what this is doing to your wellbeing and performance. If it's making you ill and affecting your work they must be told because this could backfire on you if they don't understand the cause.
If you're already aware others are also affected, encourage them to do the same.
I'd avoid asking around if anyone else is affected though, as this could be seen as gossiping / harassment.
We know poor hygiene can be affected by so many things; anosmia, being too used to it to notice, that health condition mentioned up thread, mental health issues / depression, an abusive coercive controller denying her basic rights to hygiene, nowhere to dry and air wet clothes in current living conditions. Could be anything.
There, the manager is best placed to offer guidance, support, referral to staff welfare services and so on.
And keep updating the manager and requesting action.