USCIS asked me for something that felt very minor, I responded quickly, and now it’s been quiet again for a long time, so I’m wondering if small RFEs usually slow things down more than expected or if this is just another normal waiting period.

That’s very normal and it happens a lot, even when the RFE was for something minor. Once you respond, the case often goes back into a general review queue, and it can sit there for a while before anyone looks at it again. The long silence after a quick RFE response usually doesn’t mean the RFE caused a problem, it’s just USCIS’s slow pacing and backlog kicking in again rather than a sign that something went wrong.