Not necessary. It maybe the way how your road is paved. Same car is driving perfectly on millions of other roads.
For instance on my computer Teams consumes 1% CPU when using chat or calendar and 5-6% when in the video call. Memory used 750MB.
Check if you have any third-party antivirus or whitelisting software, things like McAfee, Carbon Black or FireEye are well known bad guys.
Try installing Teams on another, clean PC. Make sure you have latest version (currently it is Version 1.3.00.26064 (64-bit) from October 27, 2020.
Try stopping all third-party agents, especially security agents, and check again. Teams is not a light App, it has tons of features and integrations.
Check that you are not using VPN. VPN and cloud services like Teams are not friends (when traffic goes through on-prem it will be slow for sure).
Report here any findings. It must be something with the paving, as the same car can drive nicely on many other roads. Could be combination too!