This was discussed during a broader discussion about routing audio from a DAW to OBS to Zoom for purposes of either live streaming for Community OM held in Zoom or recording videos in OBS (an open source video recording application)
@TheMadman_tobyjenner shared this video:
I happened to be on the Reaper website this morning and found this video on the same topic
Yes as usual a good video by Kenny, a little bit longer process in respect of recording samples, etc , as ReaInsert does all that behinds the scene and calculates the offset for you. However, the video does show how far things can by out of whack comparing the tracks. 
And I thought Kenny did a good job of explaining the latency and how it comes about.
Did the test and seems as if the Focusrite 2i2 does a pretty good. I found my adjustment was 3 samples. Assuming of course I managed to get the loopback done correctly. I did it the Kenny way. Tomorrow I’ll try the other way, see if I get the same result.