@Appointed

Edit: I just installed Libreoffice on Libertine and was also not able to solve the scaling issue.

About he scaling problem:

I have not used Libertine for some time now and would also need to figure things out.

If it did not work with the Libertine Tweak Tool, you could maybe also try to set it manually:

export GDK_SCALE=2 && libertine-launch --id <your container id>  libreoffice --writer --nologo

or

libertine-launch --id <your container id> export GDK_SCALE=2 && libreoffice --writer --nologo

You could also try to locate the .desktop file and add "export GDK_SCALE=2 && libreoffice" after "Exec=".
But I do not know, if any of this will work.