Quite a lot of low-viz experienced divers are used to determining descent speed by looking at particles floating in the water, or by simply following a slope.
I remember briefing a group of instructors (!) to do a negative entry and drop as fast as possible below 25m, otherwise they'd overshoot the divesite in the strong current (Ari atol, Maldives). They overshot the site three times in a row. After getting back on the boat again and again, jump four was successful.
Determining depth and distance in crystal clear water can be overwhelming when combined with a strong current. Especially when you see nothing but blue during descent in all directions. The experience you have until then, turns out to be of little value in a totally different environment.
For some reason, colder seems to be better. Many instructors, teaching in the cold-water areas, look down on the tropical holiday divers and regard the OW course in the tropics as useless. One reason is that the course was done in 4-5 days. The OW courses I taught in the Maldives were 9 dives of 60 minutes. That's 540 minutes of in-water experience.
The water temperature here is too cold for 1-hour dives, unless you bought your own perfect fitting wetsuit halfway through the course. And the 1-hour pool session are usually 45 minutes of in-water experience. And is 1 hour per week of diving better than 2x 1 hour each day?
The only competition element in diving should the amount of fun you have. Especially in the beginning.