Coalitions are not needed. Politicians, regardless of their personal agenda, are interested in what the voters want. They might not agree with it, they might not do what the people want, they are always interested. The other candidates, however small, provide valuable insights to them. It shows how far they can push their own agenda.
People can display their self-less submission by voting for the top 2 candidates regardless what they represent. It sends a strong signal that they can do whatever they want.
All countries get a bunch of stuff right and makes a spectacular mess from other things.
Each of those spectacles should have one or more dedicated candidates and people who are sick and tired of it should vote for such candidate. The agenda, most of the time, can be a summary of examples of other [western] countries getting it right.
While original ideas are definitely possible you can have countless [shall we say] boring topics that are absolutely worth representing.
Such party may draw an utopian or extreme picture, it may even be unrealistic. If people vote for it it will eventually send a message to those politicians who always win the election each and every time. In turn they can propose or implement a trimmed down / mild version of it or explain why they are against it.
There might be truly silly ideas worth investigating but the winning candidate cant spend his finite time in office addressing the silly things. Unless there is a significant number of people who don't think it is silly at all.
The only chance for such a party to win is if the issue is ignored or escalated to the point everyone is fed up with it. Long before that one of the bigger candidates will absorb that juicy bag of votes.
Its a slow process but it works.