Yes, it's possible to replace just the keyboard. This uses pentalobe screws to hold the keyboard in, no rivets. You won't need to order any screws. Don't screw the new screws in too tightly, otherwise it can cause other keys to be activated when pressing one key.
Make sure you have a T4, and be careful when opening it. It will take about 1-2hrs. The MacBook will not boot after being disassembled unless the USB C charger is plugged in first, just so you know (gave me a heart attack before I realised this).
You will also need to awkwardly test the keyboard before screwing it in by plugging it together and holding both halves of the MacBook, whilst plugging in the charger, so have fun :)