Weird... I'll inspect it.
Okay, found it.
So basically, if you use a different terminal than the modern Windows Terminal, there is limited support for emojis. Download and install that if you don't have it.
Another way if you have a little more knowledge is to run a few commands to enable UTF 8 (this supports emojis). (although if it still gives problems, Windows Terminal is the best).
On Windows CMD, type: chcp 65001
On PowerShell, type: [Console]::OutputEncoding = [System.Text.Encoding]::UTF8
Also make sure you have the default font. Some fonts don't support it.
As for the flickering, let me see...
It doesn't happen on mine, and I mean, my computer is old but in it's day, one of the best models. So on some very old computers, that can happen. If your computer is relatively new... I don't know, maybe try reinstalling it?
The only reason it would be my fault it's flickering is my ANSI escape codes. If I made the code badly, it would flicker, because it is inefficient. But it does not happen on mine, and I'm not saying that it's not my fault, but it is not that likely.