Could there be a very shallow sea without magic or high gravity being involved?

Hi there! As per the title, I have an idea for a region of my current DnD setting. It would be a sea, the size of the Black Sea, but most of it shallow enough that an average adult human could stand up and touch the bottom. But I don't have enough background in geology to figure out if that's possible in Earth-like conditions.

I do know that, all other things being equal, a planet with higher gravity would have smoother relief than Earth, i.e. smaller mountains and shallower seas. But this setting is your average Earth-like planet, so a higher gravity is out of the question.

Of course, since it's a fantasy setting, I could always go with "a wizard / a god / the ancient precursors did it", but if I can justify it through natural principles, it's all the better.

I tried looking for an answer on the Internet, but this is one of those questions that are so specific that it seems no one else has asked it before in the exact same way.