I've written some new install directions for rdiffweb on RHEL based distros. I've tested them on new installs of AlmaLinux 8 and AlmaLinux 10.
sudo dnf update
sudo dnf install epel-release
sudo /usr/bin/crb enable
# Python 3.12 is the default on AlmaLinux 10. Python 3.6 is the default on AlmaLinux 8
# Rdiffweb is easier to install with Python 3.12 (for example, you don't need gcc)
sudo dnf install rdiff-backup openssh-server python312
sudo bash -c 'cd && python3.12 -m venv rdiffweb && source /root/rdiffweb/bin/activate && pip install -U rdiffweb'
sudo mkdir -p /etc/rdiffweb /var/lib/rdiffweb/session
sudo curl -L
https://gitlab.com/ikus-soft/rdiffweb/-/raw/master/rdw.conf -o /etc/rdiffweb/rdw.conf
sudo curl -L
https://gitlab.com/ikus-soft/rdiffweb/-/raw/master/extras/systemd/rdiffweb.service -o /etc/systemd/system/rdiffweb.service
# Change the ExecStart line in rdiffweb.service to: ExecStart=/bin/bash -c 'source /root/rdiffweb/bin/activate && /root/rdiffweb/bin/rdiffweb'
sudo systemctl enable --now sshd
sudo systemctl enable --now rdiffweb