As a result I have to disable RFP for my site (or just be annoyed all the time), and I guess I’ll have to advise my users to do the same.
Is there any reason you ~can't~ change your keybinds to something other than CTRL+combo? You explained it's to keep from interfering with other common binds but there's still a ton available to you when taking those into account.
It's your hill to die on but I wouldn't make my website usability dependent on a browser that is so rarely seen.