Sorry for this delayed reply.
Thanks for the images! Just to confirm, the PowerBlock needs to have the USB micro connected to the PowerBlock PCB.
To rule out any software configuration issue, you could try and load this RetroPie 4.6 image that already comes with a readily installed PowerBlock driver: https://www.petrockblock.com/wp-content/uploads/2020/05/retropie-4.6-rpi2_rpi3-powerblock.img_.gz
In addition, I would suggest to remove any USB device except a keyboard to be sure not to get any interference from an USB device. The overall goal I have in mind with these actions is to find a stable status with a working PowerBlock.
Can you give me an impression until which point the boot sequence comes?