How unlikely is it for a HZ planet to have similar amounts of water as earth?

I took an astrobiology class back in the mid 2010s before a lot of data had come back. I remeber my teacher speculated that HZ earth size planets are not particuarly rare but the amount of water and other violates on earth might lie in a someone unusual goldlilocks zone that would make actually habitable planets quite rare. Essentially his argument was too much water and you'd get a greenhouse/block light out fairly fast. Too little water and you wouldn't get a true water cycle and at the time he said there was no evidence there was much that would favor planets to have roughly an earth amount of water.

I am wondering if new research has made that theory more or less likely?