Ubuntu users on 22.04 LTS or later are also unaffected, because the release came with a version that was already patched [1]. If you upgrade to a newer Ubuntu release, there is no need to pay for ESM.
Your comment makes it sound like the ImageMagick developers want money specifically from Ubuntu users to reveive security patches, which is not true.
[0] https://github.com/ImageMagick/ImageMagick/discussions/6805#...
[1] https://ubuntu.com/security/CVE-2022-48541
Edited to add some links.
You are free to criticize Canonical for their business model, but that seems off-topic to me right now.
With that said, the mentioned vulnerability is an odd one. A CVE published in 2023 with a CVE number for 2022 for a bug that was found and fixed in 2020. The bug in question is a memory leak when passing -help.[1]