To rank, yes, you generally must serve the SERP’s dominant intent, because the search engine rewards the pages that match it and you cannot force a different intent onto the position. The SERP shows you what kind of content earns the spot, and if every result is informational while you want to sell, publishing a sales page will not change the ranking. The intent the SERP rewards is the price of entry, and that price is not negotiable by wanting it to be otherwise.
This means letting go of the comfortable belief that you can publish your intent and the system will rank it anyway. It will not. The ranking reflects what searchers actually engage with for that query, so a page that answers a different intent is a worse match by definition, regardless of how good it is at its own job. You are not being penalized for ambition, you are simply offering an answer to a question the searcher is not asking at this moment.
So the choice resolves into a hard pivot: match the dominant intent to rank, or accept you will not rank and pursue the query another way. If you match, you serve the intent the SERP wants, an informational page if that is what wins, and you convert subtly within it, earning trust now and the sale later. If you will not match, then this query is not your ranking channel, and you reach those searchers through paid placement or by targeting a different query whose SERP already rewards your intent. What you cannot do is publish your preferred intent and expect the position to bend to it.
For your next target query, decide the path before you write. Read the dominant intent in the live SERP, then commit: either build the content that intent rewards and weave your goal in gently, or accept that this query rents its traffic to a different intent and choose another route to the same audience. Match to rank, or pick a different path on purpose.