I think the issue would be that DOS and BG have been more story driven RPG's rather than series like say, TES, Fallout, Far Cry etc. Which are more about being open world sandboxes.
The result is that a more open world tends to have a shallower and less interesting central story, with it being mostly ignorable through most of your gameplay. While story driven games are focused on that central story and exploration is a side element and as such it needs to restrict you to ensure that you properly progress the main story.
As far as boredom goes... I think the difference between the 2 styles merely shifts where the tedium occurs.
With a story based game, you might find the early-mid game more tedious as you play through it so often as every run.
With an open world game... Everything eventually becomes tedious as you go explore everything all the time (Unless you figure out certain places are not worth exploring like Elden Ring's many side dungeons with minor bosses and lame loot). With the main story also being far less enticing to follow through with especially after you already cleared out everywhere the story takes you beforehand.
Which is something I've personally encountered in games like Fallout 3, Fallout 4, Skyrim and Pillars of Eternity 2 where I've rarely if ever actually completed the main story because I've already explored every single place on the map before progressing it, meaning it doesn't provide me with any exp, loot or even a new place to explore so I have little interest in interacting with it.
I think the best compromise would be something like the early Bioware games. The likes of KotoR, DA:O and ME. Whereby they're story focused games that will string you along with the main story, but there are often multiple locations to go through and so you have some choice on which order you tackle them. This can allow for a little bit of extra replayability by offering a slightly different progression (Though, you normally need to go to all locations anyway so it's not perfect).
I suppose the logical continuation of this, given its aforementioned downside, would be something similar to that, but where you only go to one location and the main story continues on from whichever you picked. Of course, care would have to be taken to ensure that the story still feels interesting, reflecting your choice, rather than being some generic beat that is indifferent to which place you opted for. Like, ideally we'd get some actual "Choices matter" with each choice leading to unique outcomes and paths to choose from. The issue with this is it means you'd have to write an insane branched narrative to incorporate it (Which is why choices in video games have historically never mattered. As it takes up a lot of work to properly implement a branched story)
