If only two immortal humans distributed randomly on the Earth's landmass survived a collapse of the human population, what would be the most likely time frame for them to find each other?

Let's assume all radio systems were destroyed or they just didn't know how to use them or weren't listening to a long range radio for messages.

How would you estimate or predict the range of time it would likely take for them to find each other?

And what is your prediction?

I guess it would be some sort of calculation of movement speeds and the chances of them being within range to hear or see each other or signs of each other's existence.

Probably they wouldn't move randomly, but they'd move around bodies of water. Eventually they might use a ship or just swim across the oceans to look there too.

It could be millennia, huh?

Could go down significantly if they're both Muslims and undertake the Hajj.

Some other good places+times to look for people:
https://en.wikipedia.org/wiki/List_of_largest_peaceful_gatherings