I don’t have experience with the Resound equipment or the MDA200 (Plantronics I assume) as I use Oticon OPN S1 with a ConnectClip with a Cisco VOIP phone at work. So I don’t understand the complete chain you are using but is there a USB Bluetooth dongle plugged into the MDA200 or does the MDA200 include bluetooth? The capabilities of the device providing Bluetooth to the clip may control how well the combination works.
In my case, the ConnectClip connects directly to the Cisco VOIP phone as it includes Bluetooth and the headset profile (and others) to connect to a Bluetooth headset. The combination of the ConnectClip and my hearing aids implement a “headset” and it can be connected to my phone after pairing - the phone menu can control the connection (off/on) as long as the ConnectClip does not first connect to a computer or other nearby (and paired) device.
The microphone in the Oticon device is really an array of microphones that is directional - I need to point the clip at the sound source so clip it such that the line of the microphone screen points to my mouth and is fairly close and secured so it doesn’t move. That said, my setup also caused comments but only about excessive noise from the office environment rather than my voice (the HVAC fans are quite loud as the building is older and the system was reconfigured after remodeling - that resulted in more noise). A firmware update for the ConnectClip helped but the room noise is still a problem if the fans are running fast.
So my suggestion would be to first ensure that your phone clip has current firmware (that would probably have to be done by your aid provider unless you have the Resound programming software). Then I would check to see if the firmware in your Bluetooth dongle (assuming you use one with the mda200) is up to date as the Bluetooth dongle supplied with my ConnectClip has had numerous updates to fix issues and support new devices and software like Teams. There have also been firmware updates for my VOIP phone but that happens at the level of the VOIP software on the University VOIP system from Cisco - later versions of that have updated the phone firmware, in some cases to improve Bluetooth according to the documentation for the software.
If the profiles used by the Resound phone clip for Bluetooth aren’t implemented correctly upstream of the clip, you may have issues. Bluetooth isn’t always bug free (or complete) 
For my Oticon ConnectClip, I have to use the (Oticon supplied in my case) Sennheiser BTD 800 bluetooth dongle with my home iMac but not with my MacBook Pro from work. So all Bluetooth implementations aren’t the same. Note that a Resound company that makes high end Bluetooth headsets (Jabra) supplies a particular USB Bluetooth dongle with their high-end Evolve2 headsets - you might check with Resound to see if they have a recommendation of a particular Bluetooth dongle to use with their phone clip to ensure compatibility at that level.
Good luck