The yubikey won't help you if your passwords are weak or stored insecurely.
This has a ladder effect on your 2fa including email.
Id create a new bitwarden account with a new password with sufficient length - write it down on paper if you have to - store it on none of your devices,
Also be sure to be using a protonmail account, if you already have one change the password using the method 👇
Id then use the password generator on bitwarden to make two new passwords at the max character length Twitter & Protonmail allow respectively.
Save these passwords in bitwarden only.
Id then enable a ubikey after that for convenience.
If you still get pwned that means your computer is compromised - I would get a new one & start fresh meanwhile securing your IP address with a VPN at the router level, you'll need to purchase the router I'm speaking of.