I just tried pihole -r with no adlists and I still have no adlists:
[i] Building tree...
[✗] Unable to build gravity tree in /etc/pihole/gravity_temp.db
Error: no such table: main.gravity
[i] Number of gravity domains: 0 (0 unique domains)
[i] Number of exact blacklisted domains: 0
[i] Number of regex blacklist filters: 0
[i] Number of exact whitelisted domains: 0
[i] Number of regex whitelist filters: 0
[✓] Flushing DNS cache
[✓] Cleaning up stray matter