My first road bike (in 30 years) was an $1800 used bike with less than 50 miles on it that cost $2700-ish new, so similar price point as you're looking. I rode that bike 20,000 miles in 5-ish years. Great bike, absolutely no regrets. I "upgraded" this year to a bike that retails for $8k, I paid more like $5k, and again, no regrets. I'm pretty sure I did not need the upgrade, but I'm enjoying the heck out of the new bike.

You've already shown that you ride, so you're not going to spend $3k and let it sit in the garage, so don't worry - do you test rides and enjoy whatever you decide.

Di2 is great, but needs to be charged occasionally. It's a mature system, so no worries.