AndroidViewClient VS ADBFileExplorer

What metrics do you actually want to measure? Here is a paper in which they also compared react native to native versions: https://www.diva-portal.org/smash/record.jsf?pid=diva2%3A946127&dswid=-6692 You could use something like this to automate your inputs and measure it: https://github.com/dtmilano/AndroidViewClient (There is also a new version, but it's still in alpha development. It was also used in the mentioned paper above.)

Then, connect your phone with your PC, enable ADB debugging (under developer settings), and use something like this app to replace the downloaded watch face .bin file with your own. You can find them in sdcard/Android/Data/com.xiaomi.xm.health/files/watch_skin_local.

So what do I use personally?... Honestly, none of them. At least for nothing more than deleting files or copying them from one folder to another, for which the free version of FX is sufficient. I generally don't have much need for a general file explorer, since apps that I use that need access to online storage or SMB shares or whatever have that ability built-in (Ex. Kodi or Plex, VLC, etc.). And if I do need to manage the files on my Shield TV in a more substantial way than is possible from the most basic free file manager app, I just use adb to access the Shield from my laptop. There's a simple open-source cross-platform Python app that makes transferring files super simple, and I'm a bit of a geek so I'm not really bothered using the command line.