A small site should go deep on one winnable subtopic first and broaden only after it has won, because spreading thin across an entire topic on a weak domain wins nothing. The pivot is depth-first on a subtopic you can actually take, then expand once it is yours. With limited authority and limited resources, depth concentrated where you can compete builds something real, while breadth scattered everywhere builds a thin layer over a topic dominated by stronger sites.
The instinct to cover the whole topic, to look comprehensive, works against a small site. Comprehensiveness is a strength for a domain that already has the authority to be believed across a wide area. For a small site, attempting the whole topic means producing many shallow pages, each competing against established sites that own those subtopics, and losing on all of them. Looking comprehensive is not the same as being competitive, and a wide thin presence ranks for little while consuming all your effort.
Going deep on one subtopic does the opposite. By concentrating your content, your internal links, and your credibility on a narrow area, you can become genuinely the best resource for that slice, which is winnable even against larger sites that treat it as one corner of their coverage. Winning that subtopic earns real topical authority, the kind that the system trusts, and that won authority becomes the foundation you can extend from. Depth first is not a compromise, it is how a small site builds something the search engine has a reason to rank.
For your small site’s next move, pick one subtopic you can realistically win and commit your effort there before touching the rest. Cover it deeply enough that you are the strongest answer on that narrow ground, prove it ranks, and only then expand into the next adjacent area. Win one subtopic first, then broaden from a position of earned authority rather than spreading thin from a position of weakness.