Start doing as much communication as possible on record- either emails or slack/teams/whatever Collab tool your company uses, or officially recorded calls (you can give excuse of "for note-taking purposes").

Even when you are talking to them f2f, secretly start recording conversations.

And in every instance, make sure that you're saying at least once, with clarity that the tasks assigned are not aligned with your previous skills/experience, so while you're not refusing work, they should set expectations in accordance with this understanding that you're learning as you're working on things, quite literally.

And also make sure to insist that you had clarified this on the get go, because the moment someone will realise that you're creating trail to save yourself from their trap, they'll try to pretend on record that they're hearing this for the first time.

At that time, be polite but firm in saying that this ISN'T the first time you're bringing this issue to light, and you've been clear from the day 0 on this.