I keep seeing approvals posted by people who filed weeks or even months after me, and it’s starting to feel discouraging, so I’m wondering if this is just random luck based on workload or if filing order actually doesn’t matter as much as we think.

Yeah, that’s unfortunately very common and it usually comes down to workload and how cases are distributed rather than filing order. USCIS doesn’t process everything strictly first‑come first‑served, so cases filed later can move faster if they land with a quicker office or officer. It’s really discouraging to watch, but in most situations it’s just timing and logistics, not a sign that your case is being overlooked or has an issue.