Once the Plasma 6.3.4 update is installed and one reboots Panel Colorizer no longer behaves correctly. After the reboot I booted to have black text instead of white text on the main panel, and the other panels with a black background instead of transparent with blur.
As @luisbocanegra mentioned in that KDE Bugtracking System ticket, the relevant bug report to track is located here: [Bug]: Colorization using system colors Broken after Plasma 6.3.4 update · Issue #212 · luisbocanegra/plasma-panel-colorizer · GitHub