i don't have your exact configuration, i'm using a razor core x egpu running a vega 64 on my 2018 15" mbp.
-it charges my laptop fine, haven't noticed any issues with this
-can be flakey when disconnecting, every now and then it refuses to disconnect and i have to shut down (or unplug anyway and have it complain)
-thunderbolt cable that came with razer core x also seems a little flaky, its quite short and even the slightest movement of the laptop can break the connection
on macos it more or less "just works", but bootcamp has been a fair bit more fiddly.
i had to do a bunch of searching on egpu.io for guides on getting windows up and running at all. in several cases i ended up with an install that wouldn't detect the egpu OR the 560x inside my mabook pro and had no choice but to start over. i don't even remember the steps that i had to do to make the install work.
initially i got windows running on a dual display setup where i could use my laptop display and external monitor together. then one day that simply stopped working, and now the laptop screen stays off and only the external monitor works in bootcamp. it might have been one of the countless windows updates that broke it, but i also noticed a radeon xconnect service running that seems specifically for egpus, whereas originally it just acted like it had an internal vega64.
personally i haven't loved the experience of dealing with the egpu quirks, and its just added to the disappointment of having bought this computer exactly 2 days outside the return cutoff for when they announced the vega20 updated machines in late 2018. your mileage may vary, but even on the macos side, the vega64 drivers seem to have random bugs in the software i use, and the developers have said fixing them isn't a priority because the user base of macs with vega64 gpus is vanishingly small.
