What is the ruling on working in hotels – knowing that 20 years have passed without engaging in anything that displeases Allah – and if one earns money from this work, is it permissible to start a project with it?

If you adhere to the Sharia regulations in your work at the hotel, then your work and salary are permissible (halal). However, if you do not adhere to them, then both contain impermissible (haram) elements to the extent of the transgression against the regulations. As for money earned through impermissible means: if the possessor is poor, he may take from it what suffices his needs or what can serve as capital for him, and dispose of the remainder in charitable ways. If he is not poor, he must immediately dispose of it in acts of righteousness and for the benefit of Muslims.