Foil-hat theories about pre-Columbian Chinese voyages aside, how long did it take this knowledge to spread?
I know Columbus’ letter was popular across Europe and most European societies were pretty up to date but what about the Ottomans? Theoretically there’s no reason for it to stall but seeing as the major cause of the age of discovery was the Ottomans preventing Eastward trade would they have been outside the loop?
What about in India and the Far-East? Did they typically find out when the first Portuguese traders arrive?
I recently attempted to answer a similar question here:
How quickly did news of the discovery of the new world spread across the old world?.
I think it covers most of your questions.
Also, I know it's a by the way remark, but for your statement that
the major cause of the age of discovery was the Ottomans preventing Eastward trade
I recommend another of my old posts that shows why this isn't true at all:
'Spice must flow' a.k.a 'Ottomans stopped the spice trade and started Age of Discovery' myth