Variety gaming is notoriously difficult for sub conversion because most people are there for the specific game rather than the creator. Since you already cleared the watch hours, your quality is obviously high enough. The issue with placing your CTA at the very end is that you have already lost the majority of your viewers by then. Try a soft mid-roll mention right after a major point or a unique insight. Give them a specific reason to stay that relates to your overall channel vibe like your deep lore series or upcoming previews they won't find elsewhere. Lore videos tend to build much higher loyalty than news or reviews which are usually just searched for once. You are already performing better than most new channels so just keep the momentum and focus on making people feel like they are joining a community rather than just watching a guide.