Second monitor won't extend on MacBook Air 2020

I have a MacBook Air 2020: so, only two USB-C ports. I also have a Totu hub that has two HDMI ports. Then I have two Asus monitors with HDMI inputs. After two days of searching, I've found no article or forum that addresses my issues.

1) With the lid closed on my computer, I had one monitor hooked up and the power sourced through the hub. I left for a bit and the computer went to sleep. When I woke it up, the monitor couldn't be recognized any longer. Eventually I moved the power source directly to the computer and got the monitor recognized again. I want to take the power source back through the hub but don't know what the issue could be the prevents it from working.

2) Then I connected the second monitor through the hub using HDMI. Both monitors worked. I could open the computer lid and extend the screen from the built-in display to the external monitors, but the monitors would mirror each other. When I closed the lid to the computer, the entire screen defaulted to monitors (as they should). But I could no longer extend the screen. The dual external monitors would only mirror themselves. The computer would only recognize one monitor even though it displayed on both.

I've tried to reset the computer. I've tried to detect monitors. I'm thinking of getting a second adaptor, but then I must source the power through the hub and the computer might stop recognizing the monitor(s) when it goes to sleep. Which is why I need a solution to both even though I've figured out a work-around for the power-source issue.

Any ideas? Thanks.