I've noticed the Fold 4 wifi and cellular reception isn't quite as strong as my previous iPhone 12 Pro Max and iPhone 13 Pro.
Standing in my driveway I am able to get strong wifi6 with the iPhones and can remotely close my garage and lock my doors by phone. With the Z Fold 4 the driveway poses a challenge as the wifi is super weak to connect to the garage or smartlocks but not weak enough to automatically switch to cellular.
While driving, and on a Teams meeting, I encountered two weak cellular spots on my commute that interrupted my meeting call. The iPhones never dropped the meeting call through these same areas.
The reception on the Fold4 is still good, just observing that it's not as strong as iPhones. My Fold4 case is slim and the same thickness as my iPhone slim cases.
There are so many variables and scenarios that come in to play here
You will see this type of thing happening with any make of phone and many times even between different models of the same brand
eg a posting just today:
" received my new iphone 14 pro 2 days ago from Verizon.
My voice could be barely heard when on calls using Carplay with the iphone 14 pro.
This was never an issue with my old iphone 12 mini.
Switched to 16.0.3 last nite. Sound issue is improved but not resolved.
I spent time on the phone with Apple today and tried all the suggested fixes turning off wifi calling, cellular data.
Apple technician said this is a known issue and encouraged users to submit reports. He said a fix is in the future
but not immediate. I am considering returning phone and switching back to my iphone 12 until issue is fixed."
I was an early USB-C user and there were even inexplicable differences between dongles where Apple would not work yet Samsung did even though I was using a MacBook, all odd
I think your just unfortunate and one of these irregularities is occurring and finding the root cause is near impossible and not necessarily your Fold 4
Many well respected users here of dual OS's like Grumpymum will praise Samsung for it's call clarity over her iPhone, sometimes it's just luck of the draw or in your set of circumstances unlucky