Setting up Pi5

I have just upgraded from a Pi4 to a Pi5 to use primarily for amateur radio.
I have just connected the Pi5 to a new monitor and I can only see the bootloader, how do I get the Raspian homescreen?

What version of Raspbian? The Pi 5 won’t boot from anything earlier than Bookworm.

It is possible, if not supported, to run bullseye on a Pi5, according to a Pi engineer

Pretty annoying that Pi5 was launched as bookworm only!

I only know of Raspian which I had with the Pi4. Any homescreen will do instead of bootloader which is purely comuter text.

I think your going to have to do a rpi-update on the Pi 4. then swap that SD card to the Pi 5?

Is it not possible to download whatever the new operation system is for the Pi5 onto a USB drive and load onto the Pi5 to overwrite the SD Card?