cryptsetup: waiting for encrypted source device /swapfile, fstab empty

If I don't miss anything, everything seems fine with your configurations. However it might help to regenerate initramfs while disabling the /swap file encryption.

Boot up the system using a live Ubuntu disk. mount these two partitions:

$ sudo mount /dev/sdc1 /mnt
$ sudo mount /dev/nvme0n1p2 /mnt/boot/efi

Open /mnt/etc/fstab and comment this line (add a # at the beginning):

/dev/mapper/cryptswap1 none swap sw 0 0

Open /mnt/etc/crypttab and comment this line (add a # at the beginning):

cryptswap1 /swapfile /dev/urandom swap,offset=1024,cipher=aes-xts-plain64

Now we have to chroot into system and regenerate the initramfs:

$ sudo mount --bind /dev /mnt/dev
$ sudo chroot /mnt
# mount --type proc none /proc
# mount --type sysfs none /sys
# update-initramfs -k all -c

It's all done. exit from chroot environment:

# exit

Un-mount the mounted partitions and reboot:

$ sudo umount -R /mnt
$ sudo reboot

Now you lost the encryption on /swap. However I think you didn't want it in the first place. You might try these instructions without editing /etc/fstab and /etc/crypttab. That might work too.