The supreme commander trailer.

Strangely, I enabled it a year ago and jpegxl.info is still displaying that my navigator does not support jpegxl

Only in nightly unfortunately.

I don't think so. However, you can write a magisk module that inject content into /system.

Have you tried Shizuku or magisk's libsu ?

They both allow you to run services as root (or adb shell user with suzuku).