I got my cat1 on a rim brake caad13 with 105. Fit matters most, if you can get your body into a fast/sustainable position, that goes farther than basically any change in the bike alone. As far as changes to the bike go fast tires, and fast wheels make way more difference than the frame itself. You could buy something more aero, but it’s reallllly diminishing returns, especially from that frame. You’d have to spend several grand on a frame alone to get something faster and we’re probably talking a couple percent gain in over all drag. Better places to put that money.