Bad grinder?

Lately I have been trying to make V60 but oh god, it always bitter or hallow! No matter what I do. Grinded finer/coarser high temp/low temp changed my water from bottled water to ashbeck tesco water and still same results.

Equipment: 1- C3 Pro timemore grinder 1- hario plastic V60 3- brown hario paper filters 4- electric kettle with temp

I used light roasted beans with around 96C temp and 14 clicks, and it was slightly bitter with little to no taste. It was roasted around a month ago so I assume it is still good. I used both Hoffman’s recipe and Lance yet same results.

Could the reason be the grinder and/or paper filters?

I apologise as I have seen so many posts with the same issue and tried most of the solutions, yet same results. I even thought of buying a new whole kit just to re-learn everything.

Edit: turns out all the beans I had were stale, I just bought a few more bags and they were delicious!