You will always annoy some people who couldn’t care less about your product or a service. Regardless of how narrow your true audience is.
Of course, you don’t have to be spammy.
But there are several aspects to your questions:
Defining a reasonable target audience, clearly, in detail
Working on building a brand
Making sure your solution is really outstanding (and this is clear)
Nurturing your audience through a more complex funnel
You are only asking for the first step. And here’s a handy guide for defining your buyer persona.
But promoting to them out of nowhere will reduce your success rates big time. Lower click-through rates. No sales (from an unknown business). Etc.
Which is why building a brand matters. A lot.
Product/service quality? That, too. The more clear, niche, actionable and measurable your solution is, the better it sells. A strong brand just supports that initiative.
And the complex funnel is crucial for more complex transactions. Especially enterprise-grade deals. It’s just mandatory, nobody is pouring in 6 figures out of a Facebook ad or a landing page unless they completely trust the business or the product is used by everyone in the industry (which is kind of the same thing).