I have always experienced the random disconnects on my 2018 Mac Mini. With my recently purchased 2019 15" MacBook Pro, I'm experiencing those same exact disconnects. Regularly. (On my late 2017 5K iMac, curiously, I do not.)
According to the tech support rep who responded, the 2019 MacBook Pro has not been "certified" to work with the Envoy Pro. He also acknowledged the disconnect issue with the 2018 Mac Mini. What is really weird in his response is that he suggested turning off WiFi to see if that solves the issue. What?
... After reading your earlier post, and as I stated, it was time to do a little experimentation.
Well, after a weekend of said experimentation I can report back that my iPhone 11 Pro Max was the culprit with the OWC Thunderbolt 3 drive. Using both the Mac Mini, which spontaneously disconnected regularly, and my MacBook Pro, I experienced not a single disconnect of the external drive after I placed my iPhone in a different area of my office. Not a single one! Once I placed the iPhone next to either the Mini or MacBook Pro, the drive spontaneously disconnected.
Which begs the question: why? Improper shielding of the Envoy Pro X? Sunspots? Lunar activity? :)