there have been a few posts on here recently about that. 1 guy on a vb 218 3d printed little rubber things to allow him to use aero bars, and he got a metal shop to cnc cut him a metal plate with various holes to dial his fit.
there's also another post about aero bars that clamp on foil shape bars, made of 4 clamping bits, from aliexpress. Maybe in the aliexpress good findings thread?