There's nothing intrinsically boyfriend-y about dinner dates at all! If you haven't set yourself up as a boyfriend, and you flirt and create arousal and escalate, a dinner date is perfectly sexual. No woman (short of those living completely in their heads) is going to mistake a second date dinner date where everything is very flirty and sexual as "unambiguously on the road to boyfriend-girlfriend."
If you take women on dinner dates and get a lot of "she's trying to position me as a boyfriend candidate" vibes from girls, it's possible you're behaving in a way that leads women to react this way. If that's the case, I'd look at if you're touching, and if so, how much; if you disqualify yourself from the boyfriend role in any way; and whether you are moving women around, getting investment from them, and escalating. If you do those things, and haven't otherwise set boyfriend expectations before the date, you should not have women mislabeling what you are to them. Even if it's on a second date (just mind your framing on the initial meet + date #1).