The R5 is objectively worse because of the availability of cockpit sizes. It’s objectively slower than an SL7 if the SL7 has the narrowest available bars - whereas with the cervelo you have to use their cockpit. The bike itself is obviously an order of magnitude less significant than the rider position (consider the power difference on a road bike vs TT bike at 50KP/H for proof of position mattering).
If the 38cm Rapide handlebars ever come back in stock I’m going to buy them immediately. I’m on a size 58 bike but stuck on the stock 44cm Rapide bars (amazing handlebar, just way too wide).