Long term effects of energy drinks (anecdote)

Howdy all,

I got into the energy drink game about 12-13 years ago with Monster. Drank maybe 1 a day for a few years. Moved on to sugar free about 10 years ago and have averaged probably 600-900mg a caffeine a day for the last 7-8 years. I get routine bloodwork done every 3 months and the only abnormalities (maybe every other draw) are elevated BUN and related due to dehydration. However I typically maintain close to a gallon of water consumption a day and electrolytes. I lift weights eat (semi) healthy. Just some anecdotal evidence from me, unsure what longer term effects will be.

Edit: I am a 33 year old male, 6’0” and 225 lbs