Yes, you can use a Thunderbolt 3 dock such as the OWC Thunderbolt 3 Dock or similar available from many different makers of docks.
That dock allows you to connect the two monitors and charge the Mac via one cable going from the Mac to the dock. The second port on the Mac is then used to power the external Thunderbolt 3 hard drive.
Alternatively you could ...
In regards to question 1: Yes, it should work perfectly fine for those purposes. I use the same dock and similar 4K monitors with several setups here with the 2017 15" MacBook Pro without any flicker issues or similar. It should be the same for the 13" model.
In regards to question 2: The dock has a mini-DisplayPort port as well as a Thunderbolt 3 ...
I think you've confused Thunderbolt and USB-C.
The problems with these "display splitters" that work as "ABC" in Windows and "ABB" in Mac is that they're USB-C cables. They require demux functionality in software that macOS doesn't have currently.
However if you have an actual Thunderbolt cable then it is fully possible to do &...
CalDigit guys confirmed this issue and apparently they’ve no idea what’s going on. They insisted that this only happens to MacBook Pro 13” 2020 as they have “never received report from 16-inch owner”, and they “believe” this will be fixed in Big Sur.
So I dumped this junk and get a Targus dock, and happy ever after.