Game overlay not displaying correct Unicode characters [1.18.2] [SOLVED]

[RInventor7]

I'm using RenderGameOverlayEvent to display text on a screen. I'm reading the text in from a file using a BufferedReader. The text file is in UTF-8 encoding, I specify for the reader to be in UTF-8 but when the text is displayed some characters (öÖäÄõÕüÜ) are displayed as displayed as question marks (????????). If I set the readers charset to StandardCharsets.ISO_8859_1, then everything is displayed correctly. However, when I then export my mod and run it in real Minecraft those letters are replaced with two other weird characters making the string double its actual size.

EDIT: In the real game one character is displayed as two different other characters, then if printed out to Minecraft's debug.txt, in there those two characters are also different to those displayed in the game. 

How can I make those characters (öÖäÄõÕüÜ) to be displayed correctly not only in the development environment but in the real Minecraft as well?

Edited March 2, 2023 by RInventor7

[RInventor7]

Thank you so much. It works now perfectly.