I have a Raspberry Pi 4 Model B. When I boot it without an SD card (or when there is no OS installed on the SD card) it shows me this screen:
But when I install the Raspberry Pi OS using the Imager, it only says that there was no HDMI signal. I tried removing all partitions from the SD card, formatting the second partition to FAT, reinstalling the OS, configuring the config.txt with hdmi_mode, hdmi_force_hotplug, etc. I researched for a long time but couldn't find anymore solutions on this.
Edit: I'm using a Dell U2713H and the MicroHDMI-HDMI cable that came along with the Raspberry Pi plugged into HDMI0 Port.