How to solve error on swap creation: "skipping - it appears to have holes." (Ubuntu 22.04)

I am trying to create 1GB swap file without success on my Ubuntu 22.04.

I use the following commands:

sudo rm /swapfile1sudo dd if=/dev/zero of=/swapfile1 bs=1KB count=1MB status=progresssudo chmod 0600 /swapfile1sudo mkswap /swapfile1sudo swapon /swapfile1

The output I get:

905663000 bytes (906 MB, 864 MiB) copied, 5 s, 181 MB/s1000000+0 records in1000000+0 records out1000000000 bytes (1.0 GB, 954 MiB) copied, 5.46825 s, 183 MB/sSetting up swapspace version 1, size = 953.7 MiB (999993344 bytes)no label, UUID=4c4c204b-57ff-484d-848b-d719e0260156swapon: /swapfile1: skipping - it appears to have holes.

Context

When looking at my free space, I see:

$ df /Filesystem               1K-blocks      Used Available Use% Mounted onrpool/ROOT/ubuntu_emx73f 879401216 225886848 653514368  26% /

Note that I use the Full Disk Encryption of Ubuntu (not sure if this is relevant)

Also, replacing dd with fallocate does not solve the problem