I tried again with another computer just in case and it works:
$c: client, $s: server
$s sudo chmod 777 /mnt/hdd1
$s sudo cat /etc/fstab
UUID=301e3d8d-6c0a-4f7c-864b-4185a70efbb0 /mnt/hdd1 auto nosuid,nodev,nofail,x-gvfs-show 0 0
$s sudo vi /etc/exports
/mnt/hdd1 192.168.1.45/24(rw,sync,no_subtree_check)
$s sudo exportfs -arv
$s sudo systemctl enable --now nfs-server.service
$c sudo systemctl enable --now nfs-client.target
$c showmount -e 192.168.1.45
Export list for 192.168.1.45:
/mnt/hdd1 192.168.1.45/24
$c sudo cat /etc/fstab
192.168.1.45:/mnt/hdd1 /nfs/hdd1 nfs auto,x-systemd.automount,x-systemd.device-timeout=10,timeo=14,x-systemd.idle-timeout=1min 0 0
$c sudo mkdir -p /nfs/hdd1
$c sudo chmod 755 /nfs/hdd1
$c sudo systemctl daemon-reload
$c sudo mount -a
$c ls /nfs/hdd1