Google Docs Over-rides/Auto-corrects special characters

Hey all! I use Google Docs for almost all of my writing, and as an academic, I do a lot of writing. I have been having issues for about a year with Google Docs ignoring/over-riding special characters when I try to enter them. I have a Mac and the way I enter most special characters is by holding down the key for the similar regular character (like holding down "s" to get a menu that allows me to select "ș" or "u" to select "ü").

This works fine in all other contexts, but about half the time, Google Docs instantly reverts the special character I have just entered (e.g. "ș" is converted back to "s"). I use special characters a lot because my work involves many places globally that include these characters.

Additionally, my computer has a Swedish keyboard (I'm in Sweden) and the special characters that are part of the keyboard (ö, ä, å) always work fine. It's just when I need additional special characters (e.g. from Polish) that this issue happens. I am also able to copy and paste special characters in okay or enter them from the toolbar using Insert > Symbols > Special Characters, but I would really like to be able to use the keyboard shortcuts.

Has anyone else experienced this? Any suggestions about how to resolve this?