Possible project gaming

[Maxxryno]

I have a raspberry pi 4 2gb, and a 7 inch ELECROW Touchscreen Monitor, 7-inch for Raspberry Pi Screen - with built in speakers. Also a usb extendable wireless gamepad. Oh and if this makes a difference a NESPI 4 CASE.

I use the official adaptor for the raspberry pi, the monitor uses the micro to hdmi via an adaptor that came with it and it has to be powered. I plug

the monitor into the usb 3 port on the pi usb to usb c for the power this seems to work and after use the low power sign did not come on.

1. Would the connection of the monitor through the usb 3 cause an issue ?

2. Given that the monitor needs powering as well would it be possible to change the mains power supply for a powerbank so I can make the thing portable. I am after suggestions if possible for a reliable one.

3. Or for my understanding get 2 powerbanks one for the pi 4 one for the monitor and power it separately?

4. Major edit : Just found out the screen needs a 5V 1a power supply of its own > Will this work a 5v 3A powerbank with 2 outputs to power both the pi and the screen?>

I understand there are guides for a 3.5 inch and a 5 inch but I am struggling to find one for a 7 inch and a pi 4 .

I was looking at this to make it work ?

TOPK Power Bank, 20W USB C Fast Charging -

Capacity 20000mAh/74Wh
USB 1 & USB 2 Output 5V/3A, 9V/2A, 12V/1.5A （Max 18W）
Type C Output 5V/3A, 9V/2.22A, 12V/1.5A（Max 20W）
Type C Input 5V/3A, 9V/2.22A, 12V/1.5A（Max 20W）

however I am not married to any brand just what will make my retropie setup portable for some time,

Thanks in advance guys