Washing machine leaving brown soap residue on clothes. Tried self clean cycle. Can I fix or do I need a new washer?

My washing machine began leaving brown spots on my clothes a few months ago. I realized after doing some research that I had been using WAY too much (probably 1/2 cup or more; I filled it all the way to the MAX line) detergent, then dealing with the resulting stiffness in the fabric by using fabric softener. I’m now using approximately a tablespoon with each load.

However, since finding the problem, I have run the self-clean cycle (4 hours of hot water) probably 20 times or more, and I’m still getting brown deposits on my clothing. Is there something else I can do, or have I just completely ruined this washing machine? I know it’s not the dryer because I’ve seen the spots on clothes that I do not machine dry. If I do need a new washer, I’d like to decide soon so I can take advantage of Black Friday sales.