I believe I found a solution for this scenario. If you edit "$APPDATA%\Microsoft\Teams\desktop-config.json" and set preventUpnDetectSso to true it will prompt for credentials when switching tenants.
You do need to enter your creds once per tenant, which is a little annoying considering they should all use the same creds, but so far it looks like it remembers them between launches. So once you've gone through all of your guest tenants and entered your creds, switching between them is pretty smooth from there.
I have a work email that has been configured on my outlook, whereas, the email id used for my office 365 account is different, I don't know why my organisation did it, but, this is a problem while integrating outlook with Microsoft Teams and i need this badly and this is the only reason that we are not using Microsoft Teams in our organisation.
@Brian Mair I tried your solution, but it seems i require an exchange server in order to configure email, which i do not have in my organisation. My organisation emails are from 1and1.com, whereas my office 365 account has its own id. So not sure how to go ahead with this.
@Roberto FrancoI believe there must be a way to do this. I am on a Teams TAP team and I am able to toggle back and forth between our tenant and Microsoft's using a drop down selection next to my profile photo in Teams.