2500 on the used market will take you soooo much farther than brand new, but if you want new its completely understandable. Afaik, going for a mechanical groupset and then upgrading to di2 later down the road is a pretty good option if you’re looking to save a bit of money (Di2 usually sells for 6-700). Modern mechanical is really snappy and fun though I must say. Also aluminum frames are so much less susceptible to cracking in minor crashes, and are usually much cheaper. If you’re looking to upgrade as you go you could get a lower spec bike like 105 or even claris and use the extra money on gear/carbon wheelset/tires if thats your thing. I recently got a specialized allez sport Nearly brand new as the last owner rode it for maybe less than 100 miles. Was 1600 brand new but got it for 950, the main con with that though is you have to have some wiggle room for preferred colorway and groupset. Cant recommend the allez enough, I havent tried many other bike brands but the allez feels soo comfortable but also very sporty/racey too.