Ended up making a mainline builder script that just has Linux and busybox: https://codeberg.org/LogicalErzor/mainline_builder/src/branch/master
No root needed (for now), and this is all built locally. I'll probably expand on this to include more tools to help me mainline
This should hopefully help me use i2cdetect and other tools. I can easily kexec into another kernel now too to save my eMMC from being written to oblivion and also hopefully have more space to enable configs