We've been struggling with this issue for a while now and from what I can tell there's only one real "workaround" which involves this:
https://www.gog.com/forum/baldurs_gate_series/baldurs_gate_2_complete_crash_when_trying_to_change_character_biography_writing_in_the_journal_a/post29

But I'm 99% sure the real culprit is the GOG Galaxy installer, or more specifically the GOG Galaxy/Games folder because it has special access permissions for the user that allows read/write but not modify. You can run BG2 in it and start a new game, make a journal entry, save, make another entry and it crashes, but if you move the BG2 folder out of the GOG Galaxy folder entirely (after adjusting the install path in baldur.ini) you can load the save and do the same thing without any issues. I had ONE hang editing one of the premade characters bio after importing during character creation but that's all.

It might also be related to C:\ permissions but the whole thing is very strange. I can reliably reproduce it in the GOG Galaxy folder at first, but after moving it out of the Galaxy folder and it working, it seems like it works when moving it back in?

Not 100% sure this solves it but wanted to post it in case it helps anyone.

EDIT: Now it's no longer reproduceable. I've tried several fresh installs in GOG Galaxy/Games with or without installing via Galaxy, and I can no longer produce the C++ runtime crash. Very strange, but I still think folder and user permissions is the culprit somehow.