“…Second, the fidelity of the simulator plays a key role in narrowing the gap between real and simulation tasks. Fidelity here refers to the amount of details of the target environment are included in the simulation and how realistic these details are to be simulated (Doozandeh 2020 ). Therefore, the hardware system must be advanced to make the rendering of virtual scenes more realistic (Chang et al 2020 ), which undoubtedly leads to higher costs.…”