Interesting read.

I used to drink enormous amount of coffee at my previous work (5-6 cups a day) and the overall anxiety just became part of my daily life. Then I decided to go on cold turkey which lasted for about 3-4 months. First weeks were rough, imposter syndrome kicked in like crazy and I wasn't able to focus at all.

Now I have my morning cup of coffee with L-Theanine and that's it for the day. It lasts, the anxiety is gone and overall effect is magnificent.

Sure, try taking with coffee first but most likely the reason you can't sleep is not coffee but your body acting out due to stress. Do you sit down a lot (i'm assuming so since you mentioned 'office')? If so do you do any exercise to counteract the effects of sitting? Have you tried doing some Yoga?

What could work is to drink water with your old cup of coffee. That might sounds bullshit but, but your body is accustomed to have the coffee cup in hands. It like a smokers that have to have somthing between his fingers, and that's why they end up by eating some junk food (not all of them of course)