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.
Thank you for your feedback. We are continually looking to bring performance boosts to the Mac Client, including improvements with Electron 10 that are releasing. We are also aggressively addressing other areas of performance around the Mac client