I’m a big fan of using a dock or enclosure to reliably connect drives rather than chaining them. Cable chains can be safe and secure and work well, but I prefer one cable and hard mounting the drives:
Most basic enclosures work in JBOD mode since you don’t usually want to RAID / mirror less than 5 drives or ...
The 13" MacBook Pro 2019 supports 2 external monitors (in addition to the built-in monitor).
If you want to connect more monitors, you'll external equipment such as a DisplayLink adapter or an eGPU for hooking up extra monitors.
Given that the computer sleep seems to be the problem, I turned off the "Power Nap", and it seems to be working for me now.
System Preferences > Energy Saver
Power Adapter tab
Uncheck "Enable Power Nap while plugged into a power adapter
This seems to be preventing the computer from sleeping and my external monitor has been fine. Note that I still turn off ...