I'm a bargain hunter, but I do like good quality and I don't want my bike frames to be mostly black. That rules out a whole lot of choices.
In July of 2018 I got a real bargain on a Colnago C-RS frame, with a really nice red and white paint job. Recently I came upon an even better deal on the same frame, apparently leftovers at a US Colnago warehouse. $700 for a normally $1700 frame is a steal. You could build one up with 2020 Campy Chorus 12 speed, Zonda wheels and other top quality parts, for less than your budget. When I built mine, I used an FSA K-force carbon post, Easton EC-90 bars, SMP Stratos saddle and Zipp stem. I chose Michelin power endurance tires, that last longer than the Pro 4. Mine weighs in at 7.4 Kg, without pedals.
Here's a link to the bike exchange website.
https://www.bikeexchange.com/s/road-frames
Merlin cycles in the UK also has some decent prices on a number of leftover frames.
https://www.merlincycles.com/colnago...18-169017.html
The best price I've seen on the Chorus 12 groupset is from velomine.com
https://www.velomine.com/index.php?main_page=product_info&cPath=648&products_id=5323&zenid=snnu5pefgpo979fdt1ug2a6k