A strength ranking only means something once you know three things: which game version it covers, which mode it ranks for, and how much investment it assumes. Check those first, then read the reasoning rather than the position. That habit turns a ranking from a rumor into a tool.
A ranking is a photograph of one patch. New units, reworks, gear changes and even a new endgame mode can move a character several places. Before you use any list, find the version number or publish date at the top. If it is more than one or two updates old, use it only for general understanding of what a character does, never as the basis for spending pulls or upgrade materials.
Rankings for arena, boss damage, farming efficiency and survival modes rarely agree, because each rewards different strengths. A burst unit that wins short PvP rounds may be mediocre in a long boss fight, and a sustained damage dealer may be the reverse. Pick the ranking that matches the content you spend the most time on, and ignore placements from modes you never touch.
Many lists quietly assume a character has duplicates, a signature weapon or best-in-slot gear. Those assumptions can flip a ranking completely: some units are ordinary at base and exceptional once fully invested, while others are strong immediately and gain little afterwards. As a free-to-play player, look for lists that publish a no-duplicate, common-gear version, since that is the account you actually have.
Why do two ranking sites disagree about the same character?
Because they rank for different modes, assume different investment levels, or weigh ease of use differently. Disagreement usually means the character is situational.
Should I rebuild my team every time a ranking updates?
No. Upgrade materials are limited, and a fully built mid-tier team clears content that a half-built top-tier team cannot. Change only when your current team actually stalls.