Extra duties here can be project based. Ie; this needs to be done and it’s now part of your role to see it to completion. Also should have mentioned to ask for higher duties allowance every time you are asked to do extra.

Work to rule. No overtime, no extra duties. Exactly per position description.

I know most position descriptions have the clause “and any other duties assigned by the company from time to time. “ Comply with this, but do it poorly. Ask for clarification, training, written instructions, and still half ass it. Miss deadlines, miss data, draw erroneous conclusions.

Then get upset if called out, not angry upset, tearful upset.

Easier to clean than replace, cheaper too.