That will be the MacBook Air. You see Apple has an idea of chips go into the MacBook Pro. The 2016 MacBook Pro was designed so thin because Intel said it could make CPUs that power that thin chassis.They're just going to thin out the new 2021 design. Not a lot. Hey with rumors of a 17" OLED display for the MacBook Pro in the works (granted it's coming from Digitimes), that may be an opportunity to tweak the design then.
Apple knew what type silicon it was going to put in the 2021 MacBook Pro. These things are planned 3-4 years since release. To get to the end point: Apple was tired of hearing people complaining about thermal performance on MBP so they made cooling beefier.
If you want a thin and light, tell apple to make a 16" MacBook Air.