Do you have to own a 4K TV or monitor or does Full HD work?
HD is also possible. Like the Xbox One X too.
The Series X should also be 8K capable. And you don't necessarily need an 8k TV
A normal monitor with HDMI connection is sufficient, which can also be an SD monitor (although there will probably not be one with hdmi). The monitor then simply calculates the signal and turns 4k into what it can play
So you get a picture with a normal monitor, but it would be advantageous to have a 4k or 8k monitor, because if the xbox can do it, why not use it
Because of expensive etc.
Jagut, a normal monitor does too. If you are still interested in a 4k or 8k monitor, you can also find used ones on ebay classified ads which are usually also cheap
The same thing that already applies to cameras applies even more to monitors. Pixel is not everything. A good Full HD monitor is better than a bad 4k.
