-snip- for example by using specific verification tools such as "bitcoin-cli verifychain" or "bitcoin-cli -checklevel=4".
-checklevel is a command line option that should be added to your node, not an rpc command.
It has to be used with either bitcoind or bitcoin-qt.
It's also worth mentioning that both will use the default which will only check the last 6 blocks,
So to mimic OP's procedure, you'll need to add "0" value 'nBlocks' arg to
verifychain command to verify everything.