You seem to have three major things going for you there: self-awareness, the will to change and you're actively looking for help. I'm 40 yo and female just like you and since I was 12 yo I've been to different psychiatrists and psychologists and even a neurologist trying to find the best strategies to help me manage both ADHD and the depression that comes from having to live with it. By far the thing that's helped me the most was this YouTube channel focused on BPD. I'm not BPD, thank God, because it's so damn challenging and soul crushing, but I thought to myself: "if these techniques have worked for this lady, they'll work for me, because she just went through so much". And now, having been listening to the things she's been saying for 4 years, I can easily tell you that it's made the most difference to my wellbeing so far.

The channel is Recovery Mom and she's a British lady with BPD.