To circumvent the 'unreadable text boxes' in light mode, I have simply uninstalled/removed all LibreOffice related packages found in the Software Center. After, I installed a copy of LibreOffice by snap. This installs a clean copy of LibreOffice, meaning one that has not been themed for Solus specifically. Text boxes remain readable in both light and dark mode.
sudo snap install libreoffice
*** Update: Even though a Snap install for LibreOffice works, there are these strange 'orb' like artifacts as I will call them for now, in the place where check boxes would normally appear to select certain options. Didn't seem right. Also, the whole program would freeze for a few seconds occasionally. Utter crap; time to give Flatpak a try. So, following up from the Libre snap install, let's remove it first:
sudo snap remove libreoffice
Then installed a copy of LibreOffice with Flatpak. Can't recall if Flatpak is installed by default on Solus. Not sure either? Check with the following command that will tell you whether it is or not:
'sudo eopkg info flatpak'
If it is not, set it up: Official Flathub Solus setup page.
If or once Flatpak is installed, I installed LibreOffice:
sudo flatpak install flathub org.libreoffice.LibreOffice
Finally a fully functional and legible 'light mode' Libre!
