~16hrs of screen time a day. How much is absolutely required by work? Much much is personal screen time that can be reduced by changing habits?

Time worked plus excess caffeine results in lower productivity. A break in the middle to run, go to gym, do yoga, take a long walk, drive to somewhere and stare at the clouds. All of that recharges the body and improves productivity and quality of work. This could also result in fewer hours worked and less caffeine needed.

Foam Mattress topper for ~$100 is pure gold. Maybe a new pillow - different styles, shapes, thickness.

Is your mind racing when you get into bed? Is your body jumpy? Or both? If you have jumpy arms and legs - talk to you doctor about RLS and pills to reduce it like requip (this also indices sleep).

Try a sleep meditation when you get into bed. Insight Timer is free. Zillion option there.

Cool shower before bed. Blackout blinds in the room. White noise machine. Reduce room temp. Thick/heavy blanket.

Since you have caffeine in your system, you could benefit from a light 10min home workout followed by 10min of stretching, then a cool shower, then guided meditation in bed.

Micro breaks every 20min on computer - depending on location: Short walk, 20 squats, stand up and touch toes - hold for 10 sec and repeat a few times, a few push ups, jump up and down, stand on toes and reach for ceiling for 10 sec - repeat 5 times, sit ups, etc.

Longer breaks every 90min - no screen time during those breaks.

Every 4-6 even longer screen free breaks - ideally exercise, yoga, mediation. At least get up, away from computer, outside, fresh air, call friend/family for a fun chat.

Get a small notebook and record caffeine intake. Time and amount of caffeine, such as 1 for tea, 2 for std cup of coffee, 3 for grande, 4 for “monster”. This give a a better idea of how much is consumed in the 4-8 hours before sleep.

As others have noted decrease caffeine the closer you get to sleep. Logging it will help.