Pitcher win-loss record is one of the worst stats in baseball. It has the initial allure of something meaningful, but then delivers absolutely no reliably useful information. For starting pitchers it assigns credit and blame for teammates’ accomplishments, and for relievers a win might actually mean they blew the lead before getting bailed out by their lineup.
Individual win-loss is such a toxic stat in this full-team sport that I almost never even mention it on this site. At best it tells you what you already learned from other superior metrics, and at worst it straight-up lies to you.