When doing a manual partitioning (not with blivet I haven't tested it), if you set a ESP, boot, a third partition to be the lvm pv and there root, home, swap lv, if you check to encrypt lvm volumegroup the resulting layout is (being sda the installation disk):

/dev/sda1 - ESP
/dev/sda2 - /boot
/dev/sda3 - LUKS encrypted volume
/dev/mapper/luks-sda3 - The pv for lvm

The following lv in the luks lvm:
/dev/mapper/fedora_localhost--live-home
/dev/mapper/fedora_localhost--live-root
/dev/mapper/fedora_localhost--live-swap

And then again all the lv are encrypted:
/dev/mapper/luks-home - The lv home encrypted
/dev/mapper/luks-root - The lv root encrypted
/dev/mapper/luks-swap - The lv swap encrypted

Doing that in fedora 31 doesn't luksFormat the lvm lv's, just the sda3 partition for the lvm pv.