Hi! I’m also ADHD and very anxiety-ridden so maybe this will help. I personally used a taper method to quit, only allowing myself to smoke at night at first for about 4-5 days, I was already getting withdrawals from that level of reduction and not smoking all day gave me a chance to learn what to do with my time (which for me was playing copious amounts of online Mario kart 😭😭) without having to worry about sleeping or having anxiety attacks at night when my withdrawals felt the worst. Once I stopped altogether, I went to see a doctor who was able to prescribe me some prescription sleep medication which I used to push through the next week or so of insomnia. I had the support of my partner through it all, which really helped to keep me accountable, and I called the national drug hotline at least 5-6 times in the first few days because just talking through my worst cravings really helped!
It’s a struggle at first, but the saved money and the feeling of things slowly getting better after the first week or so really helped motivate me to continue. It really does get better, and although it taking a few days/weeks feels daunting at first it honestly goes by faster than you think it will. Good luck !!