Bojan, ZWO has a 2" Round IR Cut filter on their website for $49 USD.
https://astronomy-imaging-camera.com...ir-cut-filter/
There are a number of cheaper ones in smller sizes. You might be able to use one of the UV-IR Cut sensor cover windows and print a carrier for that. Sizes vary from 1.25 up. Don't pick an AR window as they do not block.