Create FPS stealth game

Hello, My name is Wayne and I don't have a lot of time on my hands due to work nor the technical programming experience required to make this type of game. So the game is stealth based FPS game set in a building that is 25 floors (preferably no loading as in the building is 25 floors and they are all live at the same time). The player starts on the roof or the top floor infiltrates the building collects the objective and escapes on the bottom floor via a getaway driver. Even though it is a stealth game the player can do it guns blazing if they want to and pick up weapons from enemies but they start with a silenced pistol. The other feature of this FPS is that there is a voice in the players ear where the voice has heat vision and knows where all the enemies (guards are on a the floor are) and tells the player the best way to navigate the game. (This builds into a Co-Op mode where one player has access to locations of guards on each floor and the other is in FPS mode and does what the other player says or not. If the player dies it switches the players, like how me and my friends used to play die by die on games). The enemies and objective is all randomly placed in every game where the objective is on a level between the 20th floor and 10th floor and guards are placed randomly with every level getting harder or more enemies. There are a few different types of enemies guards with pistols, guards with shotguns, guards with SMG's and Guards with an Assault Rifle. There will be a few different guards one without armour, one with light armour and one with full body armour and head gear. I have had this idea as a game for a while and I believe that this game would be best made in the unreal engine but really doesn't matter what engine. Anyways thanks for listening to my project idea and I am keen to working with you guys. Regards Wayne