Keep your chin up. You're doing just fine and now making improvements. Only you know if you're not cut out for it, but I think you're doing fine and on your way to being a great snake parent. Don't give up yet, unless you feel it's the only choice. But I think you're selling yourself short. You're currently putting in tons of effort and taking steps to make improvements. That's what good keepers do.
I also suffer from mental health issues. I've been struggling lately, quite a bit (currently working with my drs to find the right balance of meds and therapy. Not fun, but I can see light at the end of the tunnel). But my snakes are my serenity. They bring me peace. And I promise, once you have everything dialed in it gets a LOT easier. My snakes actually help tremendously with my mental health.
I hope you don't get too discouraged, you're so close!!! And once you're there it's so much easier.
Feel free to PM me with any questions. You seem like a good person, who truly cares about their pet. So I'll be happy to help you out if I can.
Keep up the good work, you'll get there...and soon.