My problems are mostly around external monitors too. I have the new 16", but I had issues on my 2014 MBP running mojave too. I have two external monitors, an A

My problems are mostly around external monitors too. I have the new 16", but I had issues on my 2014 MBP running mojave too. I have two external monitors, an Apple 27" and a Samsung 32. Sometimes the mac won't wake up my Samsung external monitor and it needs re-plugging to get it recognised (re-arranging my windows in the process). Also, if the laptop sleeps and puts the external displays to sleep, when the laptop is then woken up there's a high chance that the non-Apple external display won't wake up in time for the OS to think it's there and it will temporarily remove it, re-arranging my windows again. These issues only happen on my non-Apple monitor, and happened the same when I had a Dell monitor too. I used to have Finder isses too, though not Mojave related. I solved it accidentally by switching from Chrome to Firefox. YMMV.