For less powerful devices it has always been possible to install Gentoo in a chroot directory on a powerful computer, using a configuration appropriate for the less powerful device, compile and install in the chroot environment any packages, and then just copy all the files from the chroot directory, through Ethernet or using a USB memory, over the root HDD/SSD of the less powerful device.
I have used Gentoo in this way on many small computers with various kinds of Atom CPUs and with a small DRAM memory and small and slow SSD/HDD.
With multiple computers of a compatible kind, the files from such a chrooted installation compiled on a powerful computer can be copied over all of them and everything will work fine. If the chrooted installation is preserved, it can be updated later with other software packages and all the changes can be propagated with rsync on all other computers.
Linux is not like Windows, which will complain when run on a different computer than that on which it was installed initially.
I have used Gentoo in this way on many small computers with various kinds of Atom CPUs and with a small DRAM memory and small and slow SSD/HDD.
With multiple computers of a compatible kind, the files from such a chrooted installation compiled on a powerful computer can be copied over all of them and everything will work fine. If the chrooted installation is preserved, it can be updated later with other software packages and all the changes can be propagated with rsync on all other computers.
Linux is not like Windows, which will complain when run on a different computer than that on which it was installed initially.