If you would rather remove Dex from your phone instead of disabling it, and you have ADB and USB debugging setup, you can remove it with this command:
adb shell "pm uninstall -k --user 0 com.sec.android.app.dexonpc"
Open Settings, go to Apps. Press the three dot symbol, and tap "show system apps". Then go to Dex for PC, tap storage, clear cache. Go back one screen, tap Force stop and Disable. You might have to repeat this after reboot or software upgrade, haven't tested that.
You can use this for most Google apps not just Google Docs
Install Google Shortcut add-on. Tap the 3 dots (⋮) menu to reveal the side bar →Add-ons→Google Shortcut. Tap to open →options. From the left pane tap Google Docs and it will appear on the right pane.
(Click to enlarge screen shots )
Open a new tab and from 3 dots ...
win (meta) + up = maximize
wim + down = minimize
wim + m = maps
win + s = SMS
win + d = desktop/minimize all
win + f = finder/search device
win + k = calendar (kalendar??)
win + L = lock
win + enter = seems to also be show desktop
win + q = quick settings panel (wifi/bt etc on/off controls)
win + e = email
win + I = bixby, unavailable in DeX mode
win + P = ...
"Meta+Enter" will minimize all the current open windows on the desktop and pressing "Meta+Enter" again will reopen the windows.
You can also press "Meta+/" to view all the default shortcuts on Samsung DeX.
If you want more than the default shortcuts then you can install an app called "Desktop Hub". This app will give you lots of extra cool shortcut keys ...