The overwhelming majority of League bans are behavioural, not technical. Riot's systems are tuned to detect harassment, slurs, and intentional feeding, and they act on reports quickly and often automatically. A smurf account with a clean chat log is far safer than a main with a history of restrictions.
This matters more on a new account than on your main, because a fresh account has no positive history to weigh against a report. Two reports in the first week land harder than twenty over three years. If you do nothing else from this page: mute all, and do not type.