I have a Nokia 7 Plus RT-1046 and it connects perfectly to the above two devices from Samsung (Gear S3 and Level U PRO). The problem is that both Samsung devices have hands-free capability (you can talk on the watch and headphones alike). Before I had a Samsung Galaxy S7 and when I was receiving a call, I could answer from my watch (use the hands-free from watch) and also from my headphones.
With the Nokia 7 Plus i can't. On it i need to select which of the two devices I want as default and if i choose the headphones, it deactivates the watch hand-free capability, even though the 7 Plus has BT 5.0 and should know the same thing as the Samsung Galaxy S7 which has BT 4.2.
The other issue is the incompatibility with the Samsung Level U PRO. I can't listen to music more than 30 seconds due to the fact that after 30 seconds or less i hear a buzz or a white noise in the headphones that blocks the music. I tried to pause the music but the buzz or the white noise continues. The only thing I could do is to turn off the headphones and turn them on again. And if i start the music after 30 seconds or less the issue starts all over again. I think it might be a codec problem.
Also if I have the both devices connected (the Gear S3 and the Level U PRO) if i receive a call I can answer only from the watch. Why? Because the Bluetooth Phone Calls option on the headphones is checked but is disabled. If I want to answer from the BT headphones I need to uncheck and then check the Phone Calls options. When I check it, it automatically disables the Bluetooth Phone Calls option from the watch. My Samsung Galaxy S7 knew how to manage both bluetooth devices.
So yes, the Nokia 7 Plus has issues with bluetooth and codecs.