Two pihole servers, one n VM vlan, one on device VLAN with OpnSense delivering them both via DHCP options. I sometimes update lists, like yearly… At best. They’ve been there over 7 years. Calling them robust is correct. The hypervisors are 3 proxmox servers in cluster using ceph. Intrl NUC 3rd Gen. Less than 80w combined with all vms. Also 8 years old no failures but tolerant for it.
Iirc I seem to find whatever was configured dead or no longer the cool choice when I check online.
Whatever it is, I barely touch it and it works great. Very happy.