This is just a summary for the solutions arturo555 provided in the other thread.
In case someone else has the same issue and comes across this thread:
Solution:
Display the text that you want to copy paste in the new experimental text input object. (not a text object or text entry object).
Text input objects can be accessed and selected directly, allowing you full control, as well as copy and paste, even in online browser games.
And if you want copy-paste in order to share long IDs to connect two peer2peer players in a multi-player game:
2. solution: avoid sharing long IDs and needing to copy-paste altogether:
You can store a long ID in firebase together with a short room name, or short representative code. Just like you would store a high score. Users can get the long ID code through Firebase without needing to copy paste anything.