Can I be logged in on the Xbox One and The Xbox Series X at the same time?

just make the xbox one the home console and create a child account, job done. he will have access to any games you own if you let hime play them and gold.

I have the Xbox one X project Scorpio, I was told that the game can be downloaded in any serie X or serie S (included mine), thanks for the help!!

Game can only be downloaded on a Series S and Series X, but not an Xbox One X. Xbox One X is not the same as a Series X.

Xbox one series x can log into both websites on pc but not on mobile or console

It actually would. There's an Xbox One, One S, and One X that are all in the same family. Then there is the Series S and Series X that are in a completely different family of consoles.

An Xbox One X is not the same as a Series X. The game will not work on an One X.

Exact same thing happened to me. I was on the series x and my coins wouldn't show up. I had to log into my xbox one for them to show up.