We did a guide on How to Play COD Mobile on PC recently with the best possible graphics & resolution. This guide is to fix any common issues that come up, along with showing you the best settings for playing COD Mobile on PC with BlueStacks.
Solution for keymapping issues in COD Mobile on BlueStacks
When you first install COD Mobile on your PC through the Google Play Store in BlueStacks, the game will launch with the default device profile. In the BlueStacks Library, if there’s a red exclamation mark around the Call Of Duty Mobile app then there’s an incompatibility. Here’s how it looks –

BlueStacks recommends the OnePlus 3T for playing COD Mobile. There’s a warning that will come up if you’ve selected an incompatible device profile. When it does, click on switch device profiles.

When you select the Switch Device Profiles option, you’ll be switched to the OnePlus 3T device profile.
Once done, the game should launch perfectly fine, given your PC has the capable specs to play COD Mobile (it depends for every computer, and do remember that even emulation of mobile games can be heavy on many PCs)
Enable Smart Controls for the best controls & how to customise them
BlueStacks has a feature called Smart Controls, and you need to enable it for the best controls possible. To enable Smart Controls, go to the BlueStacks Settings Page (its on the bottom right side) and then to Game Settings.

Here, you’ll find the ‘Enable Smart Controls’ option. Make sure that’s checked. You’ll now have the precise controls in accordance to the in-game resolution you’ve selected, which by the way you need to set accordingly to your PC Specifications.
These are how Smart Controls work according to BlueStacks –
The moment you commence the game after selecting multiplayer or battle royale mode and the game starts after you have selected your desired Loadout, you enter the shooting mode automatically and hover the mouse to rotate the player’s view, shoot with left click and aim with right-click.
When during gameplay the user tries to access the map, the player comes out of Shooting Mode automatically and the user does not have to exit Shooting mode to interact with the map and as soon as the user will be done with the map and closes it, the player will automatically enter into Shooting mode again.
From the ‘Introducing Smart Controls for Call Of Duty Mobile on BlueStacks Support Page

You can also set custom keyboard controls. To do this, press the ‘Open keyboard controls’ button on the right hand side of BlueStacks after you launch Call of Duty Mobile. A demonstration is mentioned below.
From here, you’ll easily be able to customise keyboard controls. Do remember that there can be two profiles – one for multiplayer and another for battle royale. You can customise both individually.
For graphics settings, do read the guide below for the best graphics settings to play COD Mobile. We hope this guide helped you to fix any issues playing COD Mobile on PC with BlueStacks. For any further issues, leave down a comment and we’ll try to help you. You can also drop a message at support@bluestacks.com for help.
How to play COD Mobile on PC with High Resolution, FPS and Graphics with BlueStacks!