I am having a major hard time trying to remove this metal P-trap. The nut in the back will not budge no matter how hard I try. I was able to remove the front one relatively easily using some pliers but not the back. Does anyone have any tips on how to remove these metals nuts from old plumbing? Also yes there is water dripping in the back, it's not a leak just a mistake I made haha. Also if I am able to remove this, can I just replace the whole trap with a PVC one? Thank you
Yes, once removed you may use a plastic trap assembly to replace it.
You will need a bigger tool, like a large pipe wrench or large "Channellock" type plier. It won't be easy (upside down headfirst in a cabinet with restricted space) but that's why plumbers are well paid. Try soaking the nut thoroughly with a penetrating oil overnight.
They make offset wrenches for this type of job, but they are expensive. I have never needed one, just a big pipe wrench.