I know that "would" can be used in the situations below:
A doorbell is ringing. My mother says:
It would/will/could/might/may/must be John, I will open the door.
"would" here refers to something like a guess: "I guess it is John."
I don't know if "would" can be used as a guess in this situation below:
I have never learned abroad. In my opinion, there would be many difficulties when learning abroad.
Can I use "would" as a guess as the 1st situation above: I guess that there maybe many difficulties when learning abroad.