Simulation results for the disc gap at 75 au and δ = 10⁻⁴. (a) The radial profiles of the disc when planetesimal formation starts, (b) Radial profiles of pebble flux Ṁ_peb showing that it is still high around the pressure bump, yet slightly lower compared to the models at 10 au shown in Fig. 4b. The pressure support parameter η is generally a few times higher while the regions of low η still coincide with the peaks of the pebble flux, (c) m-r time sequence, showing similar results except the planetesimals are formed later and the growth rate is slower. The five simulations ended from t₀ + 1.2 × 10⁵ to t₀ + 2.2 × 10⁵ yr.