Magic Trackpad randomly disconnects over bluetooth from MacBook Pro 2018
I have this issue again and it seems the main reason is the interference between Bluetooth and WiFi frequencies. Updating to 5Ghz WiFi fixed the issue for me before in the old office but replacing a perfectly fine router with the new that supports 5Ghz is not really a solution.
Some people claim it to be a driver issue since Yosemite but I don't think so because my MBP 2012 worked flawlessly until it died in late 2018 and I had these issues with MBP 2018 since I bought it. So, my take is that it's a hardware issue caused by a bad design.
UPDATE: I've once again confirmed that switching to 5Ghz WiFi network fixes the issue. It doesn't matter whether you have both 2.4Ghz and 5Ghz enabled in your router as long as MBP connected to 5Ghz. I can't express enough how disappointing this is to have this issue in a so expensive laptop in its 3rd generation.
My endless research on this problem makes me think there's a hardware design issue in these 2018 MBPs. Or at least a firmware bug.
Some people report switching from the left to the right USB-c ports fix it, others resort to a new Bluetooth adapter/dongle. Still others say moving items on their table/desktop (physical) was the solution. I also read from someone that fixed it by turning off wi-fi and using a wired network connection.
In my case was avoiding weak wi-fi networks.
All in all, look for radio frequency activity in your environment. The solution is probably in the physical world, not in the software.
Unless Apple comes out, admits a defect, and provides an official fix this problem doesn't have a universal solution. It will require some tweaking and flipping things around you. At least that is my impression.