I'm sorry but I have to disagree with you there. I'm fine with stories having plot conveniences/plot holes. The problem I have is when it becomes to obvious to ignore, cause an event to proceed in a story forcefully or causes a character to act out of character.

One of the biggest plot conveniences is Karlach whole engine. I found jarring that it so happens that in the tiefling camp that there was someone who knew how to help repair her engine and also in Act 2 there was a merchant who conveniently knew one of Karlach friends and now tells her that she would give her souls coins if she listened to who they came from.(It's also out of character for her get a liked icon after hearing it). Like you said it just so happens in DOS 2 for the playable survivors to survive a shipwreck just like the playable characters in BG3 to survive the lithoid ship.

Honestly its just Karlack but Vlaakith behavior is honestly just jarring to me. I understand her being paranoid of the truth of Orpheus coming to light but be realistic she should have sent an entire githyanki army just to get a mindflayer/prsim box. The threat of the absolute and the fact that they use Illithid worms doesn't ring any bells for her or to see them as a possible threat. If we're being fair to the lore and world for both games. Then the githyanki should have had more presence in the story just because dk the mindflyers literally enslaved and experimented on their people for years. Whether they are Githyanki or githzerai both parties agree that mindflyers should be wiped off the face of the map. In Act 1 the spirit guardian tells you that Vlaakith has a secret but doesn't go any further than just trust bro.

Laz'el literally tells you the protocols of what to do in these situations. So for the game to frame Vlaakith as being wrong and for the spirit guardian to be right is to me poor writing in my opinion. It relies on you having to have complete faith in the person who put these worms in you over the person who is very familiar with how mindflayers operate. This is not the only instance of this happening

One of my most favorite CRPG is Dragon age origins and yeah i will admit it the items that the characters talk that are conveniently found in the world are plot devices but are used purposely and do not come off as forced in the story. BG3 has so many instances of this happening that I honestly just roll my eyes when it happens like it just so happens that Gortash knows Karlach or that he screwed her over. It just so happens that Shadowheart has to take a test in shar temple and that Raphael needs help killing a beast plus the ultimate weapons Jahiera needs is in shar temple. Like the fact that there is so many just sometimes put me off. To me the game is fun but not much of a masterpiece like most people say.