I can’t find the file from the repo.percona.com , please add the binary relase file to the repo
https://downloads.percona.com/downloads/Percona-XtraBackup-8.4/Percona-XtraBackup-8.4.0-5/binary/tarball/percona-xtrabackup-8.4.0-5-Linux-x86_64.glibc2.28.tar.gz