I have compiled rp-pppoe-4.0-1 for aarch64 and it is now available in the EndeavourOS aarch64 repository as a temporary fix.
As long as /etc/pacman.conf has
[endeavouros]
SigLevel = PackageRequired
Include = /etc/pacman.d/endeavouros-mirrorlist
listed at the top of the repository list there should be no problems updating
ppp and rp-pppoe.
For more info on the fix, see the archlinuxarm URL in the above post.
Pudge