Teams would choke on my old office desk computer (8 GB of RAM, not sure on the processor); when they recently upgraded us (now 16 GB of RAM, again not sure on the processor) it works a bit better... similar to my work-issued laptop that seems to have similar hardware. But it works the best on my Mac (iMac late 2015, quad-core i7 with 32 GB of RAM). I use it for livestreams with about 200-300 participants (I'm just a participant); meetings with 30-40 people, multiple with their video going; calling (the organization has it connected to a live phone number); and the most intensive of all, text chatting both solo and in groups... in an organization where people love their GIFs. The GIFs tended to cause the Windows machines to choke, but the Mac handles it all pretty well and it seems the most responsive.
I get the sense that Teams is pretty resource-intensive, given my experiences with performance on systems with different RAM configurations. If the MacBook Air was struggling, it makes me wonder if GPU acceleration is also a critical factor in performance.