Estimate advice

First time home owner who changes filters and gets serviced once a year for the last 3 years. My attic was making a loud clunking noise. HVAC tech said it’s because my system is extremely dirty. He showed me a picture and it looks like it snowed dirt 😅

Thoughts on the quote…
Major evaporator chemical cleaning + blower wheel cleaning $585

Or is this something I could find a diy person to do cheaper?