1 x Drivetrain with Shimano Di2 for Tri Bike ……advice pls

Think you need SRAM force Gxp cranks that have 24mm spindles?

Or go for Rotor24 cranks?

Thanks the GXP confuses me as the diameter is smaller on nds I think. The Rotor might be a good shout . Would have to change the chain ring to a 110 … but yeah interesting. Cheers