JPEGXL makes a lot of sense though. You can encode as JPEG XL and then reencode to older formats or lower qualities with minimal effort. That's part of the reason JPEG XL is set up the way it is.
Even just re-encoding a JPEG XL image into old-school JPEG using the modern JPEG XL techniques (or just directly encoding into JPEG XL style JPEG) will result in a higher visual quality and better compression ratio than just creating a normal old-school JPEG.
If you look into the architecture and design rationale of JPEG XL you'll notice that even if you don't use it as a downstream image format, just keeping it as your "source format" can give you a lot of benefits for your image encoding and delivery pipeline.
Even just re-encoding a JPEG XL image into old-school JPEG using the modern JPEG XL techniques (or just directly encoding into JPEG XL style JPEG) will result in a higher visual quality and better compression ratio than just creating a normal old-school JPEG.
Said JPEG XL style JPEG encoder (fully backwards compatible with existing JPEG decoding): https://github.com/libjxl/libjxl/tree/main/lib/jpegli
If you look into the architecture and design rationale of JPEG XL you'll notice that even if you don't use it as a downstream image format, just keeping it as your "source format" can give you a lot of benefits for your image encoding and delivery pipeline.