Hy Guys,
If you’re troubleshooting power delivery on macOS Catalina, it’s worth checking a few hardware factors alongside software tweaks. Resetting the SMC often helps, but I’ve seen cases where inconsistent charging was actually caused by a weak or non-compatible adapter. Catalina can be a bit sensitive to power fluctuations, especially on older MacBooks. It might sound basic, but using a properly rated charger makes a noticeable difference. I came across some helpful options here: https://batterysouq.ae they explain compatibility and stable charging pretty clearly, which can help rule out hardware issues while you debug the OS side.

Work Around for MacOS Catalina 10.15.5:
What worked for me is to disable System Preferences > Energy Saver > Battery > Enable Power Nap while on Battery Power; Before doing this, the external display would constantly (flicker) go dark, then come back on again. when using the closed lid clamshell mode.

Model Name: MacBook Air 7.2 (2015)
Processor Name: Dual-Core Intel Core i7
Processor Speed: 2.2 GHz
Memory: 8 GB

Displaylink Manager version 1.0.0 Build 54.71
Dell Universal Dock D6000 Product ID is 0x6006 and Version is 31.27

Go ahead and test to see if it helps to solve problem with Clamshell Mode after installing Displaylink Manager Version 1.0.0;

"You need to apply firmware from a windows Machine, I don't think Dell it will create a Mac version at all." So are you saying connect to a PC and download the firmware then hook back up to my mac?

You need to apply firmware from a windows Machine, I don't think Dell it will create a Mac version at all.

Those are only showing windows options. What about for Mac?

The link for this firmware update is .exe, do you have the file format for Mac?