Age will def play a role in whether the timelines are worth it for you. Most PhD programs should give you a stipend and cover tuition, but it's peanuts.

The Society of Toxicology publishes a paper with salary figures of it's members every 3 years. The last was in 2020

Those in industry are all over 100k, topping 150k around 10 years exp, 200k around the 20 yr mark.

Independent consulting is well over 200k with 10+years experience.