Source: https://support.parsecgaming.com/hc/en-us/articles/360012652092-Playing-Games-With-Two-Keyboards-Emulating-A-Controller-With-A-Keyboard

1-Download UCR[github.com] and unzip it to emulate the controller.
2-Install Interception[github.com] to allow for the use of keyboard inputs.
3-ViGEm[github.com] which is the controller driver.

Download it from github link, open the setup and follow the instructions.


Download it from github link, unzip to a folder of your choice and open a command prompt as administrator (Just search for "CMD" on your Windows).


In the command prompt, navigate to the Interception folder, then to the "command line installer" folder.
(To navigate, type "cd PATH" ex: cd C:\Users\YOU\Downloads\Interception\command line installer)

Type install-interception.exe /install and hit ENTER.



Simply download it from github link as in the image below and extract using WinRar (it can be a problem if you do it with the Windows decompressor).
Open the "UCR_unblocker" and then "UCR".

After rebooting, start UCR.

1. Add a profile.
   
   
2. Select your keyboard as input and ViGEm Xbox 360 Controller 1, 2, 3 or 4 as output (you can use dualshock4, but i never tested with it) and "CREATE".
   
   
3. Create mapping (Button to Button).
   
   
4. "Click to Bind" and choose a key from your keyboard then choose a button from the controller (REPEAR THIS FOR ALL OTHER BUTTONS!).
   
   
   
5. Adding triggers (Button to Axis).
   
   The mapping process is basically the same, the difference is that you have to change the "Axis on Release" to -100.
   
   
6. Press play and have fun.
   

https://html5gamepad.com/

With Remote play Together and your UCR profile active, just switch the second player to controller: