I’ve had a problem with my ConnectClip and an Apple iMac Pro (2017) desktop but not with several Apple MacBook Pro notebooks (2016 and 2019) - this was with OPN (1) and then OPN S 1 aids. When I was visiting my provider and asked about that she called Oticon Tech support - they suggested that many notebooks did not need the BTD 800 but many desktops had poor implementations of Bluetooth and needed the dongle to work correctly. Sure enough, no issues with the desktop when using the dongle but lots without it. Later versions of macOS have improved thing with the built-in bluetooth of the desktop (they sometimes include new firmware for the bluetooth chipset as the version numbers change) but the dongle is still best for my machine and ConnectClip.
Turns out the dongle was provided with many higher end Sennheiser bluetooth headphones/headsets - they recommend it for call centers where reliable bluetooth from computers to headsets is needed. Jabra also provides a similar dongle for their high end bluetooth devices.
Some collaborators at work found that some computers worked fine with an expensive (about $75K) portable instrument that was controlled by a Windows application using Bluetooth to communicate but other computers failed miserably. The instrument always worked when using ethernet rather than bluetooth. My guess is that some Bluetooth implementations are poorly done and buggy and it isn’t a high priority for some (many if I’m cynical) computer hardware and OS manufacturers.
My current More 1 aids seem to work OK with my desktop/dongle/connectclip combo but I typically use old closed large cup wired headphones plugged into the desktop as they help block environmental sounds (AC fan for example). They also sound a bit better than streaming to the aids and I can wear the aids with the headphones without feedback