Your nitrates are at 80, with a 20% water change per week.

You may want to just try changing more water. Is there a reason you
can't do 50%?

I was given some fantastic advice when I got back into the hobby a few
years ago: "There is almost no tank condition that a 50% water change
cannot improve, and there is absolutely no tank condition that a 50%
water change will harm."

Use a water conditioner that removes chlorine/chloramine of course.
Prime and Amquel are both excellent.