yes that might be a shorter path than overland. it would be my guess that in time deeper than roman, egyptian cash and goods were attractive to people in distant lands. Without going full Thor Heyerdal "Ra" they would have been capable of sailing coastal routes round if not a more direct route across the Arabian Seas

But it's equally likely they traded indirectly with any of the coastal economies around the Gulf, and Horn of Africa.

A major trade route also was from Constantinople up the black sea and then the dnipro river up to the Baltic.

Yes, via Berenice Troglodytica

>as much as half of all Rome's tax was raised at Egyptian ports

Interesting and makes sense to me. I remember reading a long time ago, when the Eastern Empire lost Egypt to the Arabs, it was considered a huge major disaster for them.

Yes, India and the Romans had extensive trade relations for the 6 centuries between the Romans conquered Egypt until the Arabs took it.

Facts: https://en.wikipedia.org/wiki/Indo-Roman_trade_relations

As I understand it, the Silk Road only became important when the sea route was closed. It lost its importance 800 years later when the Portugese found the sea route around Africa.