It is no longer true that you need a balanced party of certain specific roles. I think it's been untrue for a good long while in D&D. It's just something that people believe. With good tactics that play to the strengths of the party you HAVE, you can do well in D&D (and in BG3) with virtually any party composition. Some parties may have to be more cunning, may take longer, may need to use more consumables, but I don't think any party will be completely un-viable to complete the content.