Since I got Yubikey 5, I ended up using Yubico Authenticator. It’s a bit of a PITA since it requires unlocking with the key at each use (NFC or USB), but I grew to actually appreciate that extra layer of protection. The OTP accounts are actually stored on the key (I believe up to 32 per key), so it is highly portable.
App is decent and available for every OS, including Linux.