Disable your antivirus temporarily during download/installation. Some security tools flag BSTweaker because it injects code into BlueStacks (a typical false positive for system tweaking tools).
It depends on the game. While the tweaker doesn't "hack" the game directly, many games detect a rooted environment, which can lead to bans in competitive games like PUBG or Free Fire. Does it work with BlueStacks 5? Bluestacks Tweaker 5 -5.16.1- Download -FREE-
Right-click BSTweaker5_5.16.1.zip and choose "Extract All" to a folder like C:\BSTweaker . many games detect a rooted environment