Upgrade iPhone 6s Battery or New Phone?

I've had this iPhone 6s since January 2016. The battery was replaced in mid 2017 due to an issue that Apple acknowledged involving cold temperatures and sudden shutdowns.

Starting to notice a large decrease in battery capacity 2 years later, and I'm wondering if I should replace the battery or just put that money into a new iPhone. I spoke to an Apple employee at one of the stores in Glendale, and he advised me that the battery still had 82% overall health, and that a new one may NOT make a huge difference. However, I've noticed with previous iPhone's that they do tend to have roughly a 2-year life span on average. I get around 2-6 hours off a full charge now depending on how much I use it.

Input?