I had a rig like that a few years back.
Surface Pro with USB portable monitor.
Bunch here. The AOC is fine for the price and resolution or one of the Asus offerings.
https://www.amazon.com/s?k=usb+monitor&ref=nb_sb_noss_1
They start to get pricey when you go above 1080.
I had an AOC, was lighter than my iPad.
External keyboard and mouse.
All of it fit in one laptop backpack.
Not sure if I'd carry external speakers, if it's for calls a good quality headset is the way I would go.