There's more than one type of simulator, and F1 has certain 'spending caps', after a spending war bankrupted bunch of teams.

Wind tunnel time and aerodynamics simulator time are included in the cost cap, as are car parts and most staff (but not driver salaries, travel or marketing)

Drivers can spend all the time they want in standard consumer sim racing rigs, practising the tracks. But when it's the type of extra-high-fidelity simulator that lets you make the car better - that's subject to the cost cap.