Pi-hole v5's installer pulled an ARMv5 binary for certain PogoPlugs, despite them being ARMv6 - but of a variety that does not have hard-float support.
And Pi-hole v6 is intending to drop ARMv4 and ARMv5 support altogether, see *BREAKING* Drop support for ancient ARMv4 and ARMv5 by DL6ER · Pull Request #5445 · pi-hole/pi-hole · GitHub.
(EDIT: Quoting from that link: 'Debian binaries turn out to cause unsolvable SIGFPE on ARMv6 and lower.')