I had missed the fact that it's version 2.63 that's running:
May 2 15:31:09 leonardo snapd: daemon.go:247: started snapd/2.63-0.el7 (series 16; classic; devmode) centos/7 (amd64) linux/3.10.0-1160.119.1.el7.tux.
But snap list gives:
Name Version Rev Tracking Publisher Notes
certbot 4.0.0 4557 latest/stable certbot-eff✓ classic
core24 20250318 888 latest/stable canonical✓ base
snapd 2.68.4 24505 latest/stable canonical✓ snapd