Import private SSH key fail

[JuniperCisco]

• YubiKey Manager version: 4.0.0
• How was it installed?: Official releases site
• Operating system and version: Windows 10
• YubiKey model and version: 5 NFC, v.5.4.3
• Bug description summary: Import of private SSH key fails, none of the passwords work

Steps to reproduce

1. Generate an SSH key on the PC (RSA-4096, no passphrase)
2. Run the following command: ykman piv keys import 9d /id_rsa
3. Enter PIN when prompted.
4. Password prompt appears (Enter password to decrypt key: )
5. Tried entering empty passphrase, correct passphrase, user account password, nothing works.

Other info

I want to use the YubiKey to authenticate on my network equipment. RSA-4096 is the minimum allowed key strength, but it cannot be generated via GUI or ykman CLI tool, so I want to import the key. After some research, I realised that 4096 keys are not supported by PIV it seems. I tried using ECCP256, but ssh cli tool and every session-manager I've tried do not recognise those type of encryption. Any help would be appreciated.