When I started traveling more around Europe for extended periods, I still needed to do my job, and I wanted as much screen real estate as possible. I had a hacky solution years ago, using an iPad as a second monitor, but I needed something larger, and the Lepow portable monitor was the perfect upgrade solution.
This portable monitor and two laptops fit in my travel backpack and tech duffle. The cover doubles as a stand, and the only complaint is that you must use the provided USB-C to USB-C cable to connect/power the monitor, and I have not had any success with other wires. I love that the same cable that sends the signal to the screen also powers it, so I do not need to carry an additional power adapter. It can eat your battery, so make sure you have power nearby.