There is no ending in Realmz. Its just a big open world. And as you dig, you find more, and more and it just keeps going. But there is no particular path to take. You just can go anywhere and find adventure along the way. There are a huge number of random encounters, and the combat style is basically top down tile based D&D, which BG3 is also, more or less.

Just to comment further, if you're not a big fan of Baldur's Gate 3 (or the Paths of Exile series, to name another popular modern RPG) for that reason, I wouldn't recommend the Avadon series in the Spiderweb Software bundle, as it has the same sort of streamlined "move you through the world to the right places" thing. The Exile/Avernum series has the Realmz-style "go wherever and stumble onto stuff" model that you're referring to.

Kind of reminds me of the difference between Fallout: New Vegas and The Outer Worlds. Like, both are...technically open world games, but there's very little reason to ever backtrack in The Outer Worlds, and not much placed content to stumble on outside of cities, whereas in Fallout: New Vegas, I'm running all over the place and running into all sorts of stuff, without having the game really drive me in one direction.