Very much doubt this is true from any standpoint based on the fact youtube offers an Embed Link for you to embed the video stream wherever you please.
Noy saying you are flat out wrong (meaning those interested need to go read up the legal yourube crap for themselves) but based solely on the fact they allow the behaviour by design, you may be…
There is a way to stream YouTube (and possible similar platform videos) in Unreal Engine 5, outlined here [UE5] VidPlayer - Video, radio streaming player
Notice that the outlined solution probably requires stream URL updates from time to time. But it shows a way to stream YouTube from Unreal without extra plug-ins and should be good for live streams, testing, and in case the URL uptime is sufficient.
If its based on the botched Web display thing, then its just not going to work.
Its basically whatever ancient version of Trident they built into the engine.
If you knew enough you could attempt to get some source from Chrome and implement your own web browser thing that you will also need to keep updated with each release - and over they years (of disuse) it would completely stop working.
It goes back to whatever they said above.
If you need the video to exist and keep existing through time, you need to download it and package it with the game.
Otherwise, you are pretty much stuck with the web system you come up with or that epic comes up with - which many times just doesn’t work… (like the whole engine? How nice hu?)
There is another (free) browser on the market which I think works for YouTube (not tested recently), but this is not feasible since I need YT display in a market place project.
https://www.unrealengine.com/marketplace/en-US/product/lambda-web-browser
