I’m expiriencing that issue too, but it’s most likely your controller’s and not entirely the game’s fault.
Since a heavy attack or using the bow needs to register about 90% (probably a bit flawed game design) of the analog R2 trigger and your propably quite extensive used R2 delivers below that, the game won’t register.
To check if this is the case with your controller, do the following:
-> Plug your controller into your pc
-> Go to ‘Devices and Printer’
-> Right click on ‘Wireless Controller’
-> Click on ‘Game controller settings’
-> In the window that pops up click ‘Properties’
X-Rotation is L2 and Y-Rotation is R2.
If you press L2 and R2 at the same time and the bar called Y-Rotation doesnt fill up as much as the X-Rotation, then that means that your R2 doesn’t register the full 100% of analog input (provided the L2 is functioning correctly).
Hope this helps to clarify things a bit