The Console will only be visible on your PC screen! NOT in your headset! So make sure you have “ Half-Life: Alyx” running. The Console can now only be opened when the game is running (!). Half-Life: Alyx: Launch Options How to open the Console and Enter Commands Opening the Console
Now personally I believe that cheats have a tendency to spoil the game, so I’m just saying this again: But not all commands are cheats, some can actually help you tweak the performance on your rig (often at the expense of picture quality etc). Some of these commands allow you to enter “cheats” and become invincible, or spawn weapons or other objects, switch maps, turn on the flash light, etc. In essence the “Console” allows you to enter commands to be executed by the game engine (Source 2: Developer Page, Wiki Page). If you’ve never tinkered with the console commands in previous Half-Life games, then this may be a new one for you (Half-Life is not the only game having a “Console” option). How to open the Console and Enter Commands.
