New oven still puts out terrible odor 5 days after buying?
It is a normal experience that every time you use a new appliance with a heating device, you will smell something weird like burning plastic. I recommend you to read on the link below on some tips of getting rid of chemical residue (smell) from your new oven.

https://www.cnet.com/how-to/why-you-should-always-burn-in-your-new-oven/

If this is not effective, try my experiment which did a great wonder. Pour some water into a pan and add a teaspoonful of cinnamon powder into it, put inside the oven and set it to 250°C. You may also use a tablespoonful of vinegar as a substiyute.