I have 3 accounts in teams. Two are in client tenants and one is my personal. I haven't had any issues because I can't work on more than one customer at a time. I still get notifications from the other clients when I'm not actively staring at things. I could leave teams off all day and still be fine. The business requirements don't change that quickly in my part of the world. If you are doing 1099 for multiple customers, you should not let them dance you around with instant messages in real time. That will wear you out very quickly.