Not the fan, not even remotely. Having this same echo issue. Using a Company Provided Laptop - Windows 10 Enterprise , Surface Laptop Go Model 1943 i5 - must be connected to a company VPN at all times due to the type of work I do.
Anytime I am on a teams meeting with someone, if I am not muted, I cause anyone speaking to echo badly - as in their words repeated .5 seconds after they say it initially.
This occurs whether I am remote, working in office, using a headset with a mic, using my laptop mic. Teammates I meet with do not experience this issue on other teams calls that im not on, and I do not have this issue when meeting on Zoom or WebEx.
I unfortunately have to use Teams, as that is the company wide preference for meetings - and not all of our people can be in office at all times/some are completely remote 100%. This is really not efficient for collaborative work, as the mute button is not as quickly enabled/disabled (even with keyboard shortcuts) when trying to discuss back n forth. Also my manager feels terrible having to constantly keep me on mute when im actively contributing to the meeting.
I find it odd that this has been an issue since (at minimum) 2021, but there has been 0 real fixes actually posted, or that this has been acknowledged as an issue. Please fix, my IT guys have finagled every laptop setting possible and nothing has fixed it.