Great question — answering as the UphillTech team:
I suggest using a tool such as Linux Respin ( source code ) or Linux Live Kit which you can use to build a bootable ISO (if your Linux from scratch distro supports it). You can search for a tutorial, like this one.
Full answer by 562679: https://unix.stackexchange.com/a/607900 (CC BY-SA 4.0).
Need it done for your business? UphillTech.
