Two of my soft keys don't work.

I have an android 7.0 Nexus 6, and it has three problems: The home button doesn't work, neither does the recent apps button, and notifications will sound but won't show up. I've tried many ways to fix this, but to no avail. Nova Launcher's Setup Wizard doesn't work, restarting my phone in Safe Mode doesn't work, and changing users to guest and back to my main account doesn't work.