On both my Fedora laptop and on my MacBook, I have to enter a password at boot to unlock the hard drive, and both had similar complexity to set it up (in Fedora I clicked a button and entered a password during the install, on Mac I clicked a button and wrote down a backup key after the install).

I think this is specifically for the TPM2 integration, which isn’t required for FDE. But I assume it makes it smoother. System updates that requires multiple reboots for example are more annoying on Fedora, since every reboot requires re-entering the password, while on Mac I just login after the final reboot.

FDE without TPM requires the passphrase to have as many bits of security as you want the encryption to have. With a TPM you can have something as short as a PIN, since the TPM can limit the rate at which password attempts are made. I assume most users are satisfied with the weak security implied by a short passphrase, but a dedicated attacker could likely crack it.