This is where a fundamental difference between Baldur's Gate 3 as a computer game and classic Dungeons & Dragons as a pen & paper game appears. I've been playing D&D for over 40 years, from first edition to fifth edition, and would say that D&D has infinite replayability. Some of my favorite campaigns, for example Ravenloft, I played several times as a DM with different groups, and even that didn't diminish the replayability. The core reason for that is that in D&D the campaign main story is only ever a background. The really interesting stuff is in the emergent stories and roleplaying of the individual characters.

Larian Studios put more effort than most other game studios into the stories of the characters in Baldur's Gate 3, including some range of choices and variations in interactions between them. But even they can only do so much. I can't replay Baldur's Gate 3 with a completely new set of companions whose story I don't know. For any given companion I might be able to make one major different choice, but I already know that this doesn't change anything in the main story, and just results in a minor variation of the epilogue you see at the end.

The most significant choice I can make about a companion is not picking him up. On replaying, I basically have the choice between going through a lot of same or similar dialogues with for example Gale again, or simply never letting him join the party. You can play with 4 custom characters, or get hirelings from Withers. The only Origin character you can't totally avoid is Shadowheart, as her story is so closely related to main events of the story that the game forces you at some point to add her at least to your camp. Thus one possible way I see to replay Baldur's Gate 3 for me would be playing Shadowheart as an Origin character, but then choose 3 custom characters to make up the rest of the party, and never let anybody else join. The obvious downside to that idea is that it would result in a much story-poorer game. There would be a lot fewer dialogues and cut scenes. And some parts of the story would simply still be there, but lack believable motivation to pursue: Why go after Cazador if you never met Astorion?

And that is where I am with my thoughts on further replayability of Baldur's Gate 3: A choice between playing through the same companion stories again with minor variations, or skipping those companion stories and playing a version of Baldur's Gate 3 that lacks much of what made the game such a success. That contrasts with the only other 5th edition D&D game I know, Solasta: Crown of the Magister. Solasta has several DLCs, one of which, Lost Valley, offers a completely new level 1 to 12 campaign. That is obviously only possible because Solasta had a much smaller budget and there weren't so many millions invested in NPC motion capture and voice acting. But the advantages for replayability are obvious. And Solasta 2 is coming out in 2025 already, while we will have to wait many more years for the next Larian game. Baldur's Gate 3 is probably the best computer role-playing game ever, but it is not as if that didn't come with a few downsides.