I used to have that problem with Ctrl + Q and Ctrl + Shift + W. I used AutoKey to map them to an empty AutoKey phrase.
AutoKey lets you target only specific types of windows if you want, so you can additionally limit these mappings only to the browser.
You can also map Ctrl + W to an AutoKey script that converts it to Ctrl + Backspace: keyboard.send_keys(“<ctrl>+<backspace>”)
The difference between phrases and scripts in AutoKey is that phrases can only output dumb text (and expand some macros), whereas scripts are Python code that can do stuff with the keyboard, mouse, windows etc.