I’d prioritise aero and handling, so Allez Sprint is an excellent choice (I used to have one).
Deck it out with Sram Red 11/Force 11 and some 1500g carbon wheels and you should be fairly close to 7kg.
I had my Allez Sprint (49cm) at 6.8kg with Sram etap and 52t 1x chainring.
I don’t see the need for disc brakes for a crit bike, adds to cost and maintenance.
I’ve changed my bike fleet a bit, and I’m now building up an early 2000s Principia Alloy frame for my Crit/winter bike with aero forks, aero handlebars, Force CX1 with 54t chainring and Powertap Carbon wheels, should cost me less than £1000 in total.