Not to come off as dismissive of your concerns but it's basically a rite of passage for a late-diagnosed ADHDer or autistic person to collect at least one mood disorder before arriving at the correct diagnosis. If you're AFAB or PoC then you can pretty much expect to run a gauntlet of mood disorders before you reach the finish line.

Try not to invest too much in the label - it's just a descriptive term but the condition that you have, whatever it happens to be, and the symptoms you experience are the same today as they were yesterday. You could call yourself haunted, you could call yourself bipolar, you could call yourself mad; that doesn't have a determining effect on what you're dealing with.

Obviously I'm not saying that you should go collecting diagnoses or that there isn't a degree of impact that a prior diagnosis may have on the type of treatment you receive but try not to get too caught up in the whole thing.

As a personal example, my psychiatrist has broached the idea of a diagnosis of chronic fatigue with me on multiple occasions. Each time it has been mentioned I have expressed my reticence towards it - I am not in the business of collecting diagnoses, a chronic fatigue diagnosis doesn't open up opportunities for better management or treatment of what I'm dealing with than what I already have, and I don't really need clinical validation where it's basically saying that I'm tired all the time, except it's Medically-Approved™. For me it seems as though getting diagnosed with chronic fatigue would serve no purpose and so I see no use in it. Whatever it happens to be you can name it, you can choose not to name it, but ultimately if naming it doesn't create opportunities for you - whether that's a better way of understanding and managing the condition, more avenues for treatment, access to supports and accommodations, or that sort of thing - then a label is not a useful thing and in that situation I'd seriously consider whether I need to carry it with me at all.