The engineering team is continuing to work on adding support for multiple accounts on desktop clients. We will first launch support for 1 work/school account and 1 personal account so users can enjoy Teams for work and personal side-by-side. Windows and MacOS. Support for multiple work accounts is still being worked on and will come at a later date.
You can track status via the roadmap here: https://www.microsoft.com/microsoft-365/roadmap?searchterms=68845.
Due to a priority shift this request has slipped to the backlog. I hate to bring bad news. I will continue to provide the feature team your feedback and votes.
Hopefully this will move back up in the queue soon.