I too used to run 20 charts similar to what you have but over time I switched away from Currencies after much testing to just two Index charts, the Hang Seng Index & Dow Jones Index.
I usually trade the first two hours of the open of both Indices which are like 12 hours apart from each other which can be a pain on the old sleep cycle (but you get every weekend off
I tend to look at 4hr & 1hr for analysis then drop down the the 15 min for trading.
This is what my 4k screen looks like (which is the top half of the screen, I keep the bottom half for Kodi, Internet & looking at code etc..
All the best