What version of:
I currently run a MacBook Pro (Intel) purchased in 2020, with Big Sur fully updated (not going to Monterey until I am certain all development tools I use are stable), MS Teams, and Obsidian open constantly.
Several types of Teams calls throughout the day, switching to and from Obsidian to take notes during those calls (and throughout the day), with no issues.
The fact that you close Obsidian and reboot your laptop leads me to wonder if there is something else at play.