Impact of ²²Ne diffusion on the WD cooling times, defined as the time since the star reaches its maximum effective temperature at the beginning of the WD phase, for cooling sequences with standard ²²Ne abundances and different core chemical compositions. Solid lines indicate the ONe- and CO-core cooling sequences of 1.10 M_⊙ disregarding ²²Ne diffusion, whilst dashed lines illustrate the behaviour of 1.10 M_⊙ sequences with ONe and CO cores that consider the impact of ²²Ne diffusion. Right panel: resulting time delays (in gigayears) relative to the 1.10 M_⊙ ONe-core WD cooling track of Camisassa et al. (2019) that disregards the ²²Ne diffusion process. Filled squares indicate the onset of core crystallisation in each WD sequence and the shaded area indicates when the model overpasses the Q branch, that is, the region where the cooling delays are revealed by the observations of Gaia.