MQTT-Controlled Gapless Video Playback on Raspberry Pi 4 & 5

We require a skilled freelancer to develop a script or program that allows a Raspberry Pi 4 and 5 to play a specified MP4 video file with audio from a local SD card directory on a specific HDMI port in full-screen mode without any controls or borders with seamless transitions where required.
The video playback will be triggered via an MQTT message specifying the file name (see node-Redscape in references below for the model that will be employed)
The information and outline in this document constitute a ‘test’ environment, and various details and settings will change. The project must allow this information to be changed easily, preferably in one configuration file in plain text for operators with limited technical knowledge.

UPDATED with FLOW Diagram