I noticed a fair number of masks being worn in Athens, GR, more than other places, save Oman. There was basically zero impact by COVID on our trip. We were asked three questions prior to boarding, that was it. (We didn't go very far into Oman for other reasons.)
The elevators on the ship would get packed as folks returned from shore excursions. Some older folks asn Asians wore masks.
I saw various older signs about the six foot thing, nobody cared, at all.