Reinventing the wheel 101

I don't like that you killed A/B updates.
Everything else seems fine though.

but sure I guess you can enforce that theres no more /data/adb/modules_update

If you need, feel free to open a PR.

yeah right, I guess I can't really say shit since I can't rust.

When we use overlayfs, all the data of the modules is packaged inside the ext4 image, and the data is consistent; however, once the modules are placed in a directory, this advantage is lost, making AB updates less natural. There may be good solutions, but we haven't thought of them yet. Our priority is to advance the metamodule first.

metamodule can handle A/B but we have to be sourced on top, right before installer.sh.
then we can handle mv -f modules_update/ modules/ on metamount

You can use metainstall.sh, complete your tasks, and then call install_module.