Why are you using multiple partitions ?
Linux is not like Windows where you can run programs on any partition or inserted media ; you can only run executables on the primary boot partition. Its therefore pointless IMO to have more than one partition (plus a swap partition).
Have you tried asking ChatGPT or Gemini ?
This is what Bing said :
Fixing “Gave up waiting for root device” error in Debian The error “Gave up waiting for root device” in Debian can be caused by missing modules or incorrect partition references. To fix this issue, you can follow these steps: Boot into a live session and list the UUIDs of all partitions using sudo blkid. Check the /etc/fstab file to ensure the correct UUID is listed for the root partition. If the UUID is missing or incorrect, replace it in the /etc/fstab file. If the error persists, you may need to rebuild the initramfs file by running sudo update-initramfs -u after installing the necessary modules with apt-get install lvm2 cryptsetup if you are using logical volumes. 1
These steps should help you resolve the boot error and restore your system’s functionality.
source :Ubuntu
It could be a hardware issue. I’ve found that if the screen drivers fail it usually switches to a text console or reboots into one. Assuming you have a laptop, does wiggling the screen make any difference. If its a desktop, try wiggling the power connector or video cable (both ends) and along the cables, sometimes stress can break the wires in the cables if they go around a bend.