I'm sorry if this question has already been asked but I've been looking for a while and I can't find anything that's really helped.
I recently got a Raspberry Pi 4b but when I connect it to a screen, green and red lights flash initially and I start to see it boot up but (with a one time exception) it crashes before it has finished booting and the green light stops flashing. Before it crashes it shows a rainbow screen then shows 4 of the raspberry pi symbols in the top left and sometimes starts to have the text below it before it crashes. When I boot it without an SSD, the red light is on and the green light flashes 4 times on a loop. I've tried everything I can find but this seems to be buried under the SPI EEPROM problem and I can't seem to find anyone else who has quite the same problem.
Any advice would be greatly appreciated.
EDIT: I have since tried it with the official raspberry pi power supply and still have the same issue. I have also read through the pi4b post in the sticky and none of those issues seem to be the case (I do get the 4 flashes with no ssd so it's not the EEPROM issue, I have been using blank versions or raspbian on both a 16GB and a 32GB ssd, The green light gradually stops flashing and does not flash regularly, I only have the power and microHDMI plugged in (I've tried 2 separate cords for both)).