Answers
Can you have more than one account on a messaging app?
On platforms identified by email address or username, usually yes — a second address is a second account. On phone-number platforms it requires a second number, which is the practical obstacle.
Separate accounts for work and personal is the usual reason, and it works cleanly when the identifier is an address you control several of.
The complication is notification management: two accounts in one browser generally means two sessions and some switching.
On Naven a second email address is a second account, with no phone number required for either.