The Vienna System

My second recommendation when playing White is to start with e4. There are certain pros and cons that come with playing e4 instead of the London (d4), (…). The pros of e4 are increased variety in the positions you can get, and in e4 games there are situations where you can be completely winning in the first ten moves (…). That is not something The London System ordinarily offers, apart from situations where your opponent has blundered their queen - which has more to do with their playing like a bozo than it does your opening (…).

The downside of playing e4 is that Black has six or seven opening moves that respond to it, (…), the way to study e4 is to study Black's two most common response moves. After that we’ll look at some of the overarching theory associated with e4 games.

(Rozman 2023, 286 chap.2 part.1)