I was (and sometimes still am) on more than you. Maybe I am lucky but several times when I have stopped buying via the internet because of constant fraud on my bank account (I cannot mention sources but strike up a personal, friendly relationship with a dealer and NEVER order from Pakistan no matter how cheap they are !) I have gone from 1000mg daily to nothing, at a stroke and for up to six weeks at a time. Codeine helps but in the US you will have to do CWE. My one problem is inability to sleep. Once, I did 28 nights, and the following days) in a row without a wink of sleep. I find I begin hallucinating after ten nights (at which point my doctor gave me ONE 5mg tablet - idiot !). Also I get tempted to neck 2-3 bottles of strong wine which not only costs more and although it does not stop me working ( I am retired now), I tend to look for excuses not to do a thing. But legal tapering is impossible for me as no doctor will start you (in the UK at least) on more than 30mg daily which I cannot even notice !There is a lot of hype about tapering. Your state of mind is the key. I have convinced myself I do not do illness, and I have not had even a cold since I was 10. I don't do seizures either ! I am not suggesting you follow my example or that you should not take the matter seriously but I can verify that it is not a "fact" that cold turkey is impossible. Seizures are caused by over activity in the brain cells which have become used to sedation so, if you are worried about that, switch to another sedative. The new "Z drugs" use the same receptors in the brain as benzos. And, at the rate you have been using those, are very unlikely to send you to sleep. Alcohol is also a sedative drug and probably reduces the risk of seizures, but is really the worst alternative because it damages other parts of the body, especially the liver, and is far more likely to lose you your job. On the other hand, there is a cross tolerance with benzos so you will probably be able to take more of it than "normal" people.
Many people will disagree with me but, kept within limits ,alcohol could save your life. But I would suggest codeine as a substitute for diazepam/Valium. In the US I think you can only get 10mg or 20mg tablets. In the UK there are 60mg tablets, although 2x30mg is cheaper, while up to 600mg is legally available as a linctus under a pharmacist's supervision without a script. In fact, a chemist would not be breaking the law by filling a 500ml bottle from a larger one, and a few still do. Otherwise do a CWE but I would suggest with paracetamol (called something else in the US) and not with ibrupufen because it is harder to extract and is toxic in long term use, even if it is available in every corner shop. Be careful, too, with paracetamol if using alcohol because both damage the liver. Codeine, though, although it is not strictly a drug but a pro-drug which has to be metabolised to morphine (also in the liver) is a benign substance which I have used (both with and without diazepam) for nearly 50 years. It is a pity that the US has such an irrational fear of it. In Iran (don't go there for it !) both 30 and 60mg tablets are OTC medicines and, at least until recently, and for all I know still, both tablets can be bought OTC whether strictly legally or not in Spain. Oddly enough the same applies to diazepam, etc, in India but, for some odd reason, the country has followed America in making codeine virtually impossible to obtain, even in cough mixture !
To summarise, I can only help you from my own personal experience. There are good reasons for quitting diazepam and indeed all benzos, one of which is the possible connection wtih Alzheimer's Disease (although if you read the report from Strasbourg University, published in, I think 2012, which stopped most doctors prescribing diazepam, in particular, in the UK, and study it with care, you will see it is fatally flawed. Alas, I do not have the space here to say why, but it is worth reading. I know seizures are a possible risk, but do not assume they are inevitable and treat what you read of the dangers with the proverbial "pinch" (or sackful !) "of salt ! Finally, if you are going to taper, there is no point in tapering below 15 or 20mg a day. Everyone I know who has done tapering has simply stopped at about that point with no ill effects. Cutting up 2mg tablets with a razor blade is a pointless exercise. I hope this helps you.