Is factory resetting from recovery or settings better? (LG Q6)
There is no difference - one depends on another.

When you select "Factory Reset" from Settings, it reboots your phone into recovery and wipes there. So there's really no difference as the actual process only takes part in recovery mode. You may choose whichever way for you: Navigate through Settings or use physical buttons - the latter is useful when your phone doesn't boot or the touchscreen malfunctions.