Yubikey support in Zoho Mail?

I currently have two accounts on Protonmail - one personal and one for business - but I'm getting fairly annoyed at some longstanding bugs in their mobile client and I'm looking to switch. I also want to use Yubikeys (something PM has long promised but still hasn't delivered).

I found pages saying Zoho supports Yubikey for authentication, but I have two questions I can't find the answer to:

Can multiple Yubikeys be tied to the same email account? Such as a primary one and a backup one?
Can the same Yubikey be used for more than one email account? I wanna maintain separate accounts for business and personal use. Edit : want to use the same key as 2FA for both of them

Dinar Detectives

Zoho Desk Resources

Desk Community Learning Series
Digest
Functions
Meetups
Kbase
Resources
Glossary
Desk Marketplace
MVP Corner
Word of the Day

Topic Participants
Robert
Dominic Sagayaraj Johnbosco

Sticky Posts
Deprecation of SMS-based multi-factor authentication (MFA) mode
Overview of SMS-based OTP MFA mode The SMS-based OTP MFA method involves the delivery of a one-time password to a user's mobile phone via SMS. The user receives the OTP on their mobile phone and enters it to sign into their account. SMS-based OTPs offer