Assuming you've tried the medication route, there's one that not too many psychiatrists are aware of for its off-label depression use, specifically for treatment-resistant depression: Modafinil.
Don't let a cursory search warn you off, it is not a traditional stimulant, and not considered addictive. It can also be an excellent second-line treatment for depression. It's what keeps me functional during periods where depression bleeds through my normal treatment plan. Check out this article: https://pubmed.ncbi.nlm.nih.gov/16035049/
