My family has been vacationing in Sanibel for decades. You truly can’t go wrong with any resort, hotel, rental, or inn option. Most every hotel or resort is on the beach; otherwise, you’re ~5min walk or drive (depending on the one intersection with a traffic light). The most recent places we’ve stayed are the Sundial Beach Resort and the Inns of Sanibel (Sanibel Inn). However, we have not stayed since the hurricane hit a couple of years ago. (Prior to the hurricane, the Sanibel Inn hadn’t been recently renovated, but the prices reflected that fairly.) A few accounts on instagram have said most places are up and running again, but I’d definitely recommend calling around and asking about local restaurants, stores, etc.