I recently did a one night staycation at the Shangri-la Rasa Sentosa. While it isn't really a luxury property it is the only beachfront hotel in Singapore so that will certainly appeal to some. I booked a luxury circle rate for 455++ SGD for a deluxe sea view room which was upgraded at time of booking to a pool view room although I preferred the sea view so the hotel was able to change the booking to a panoramic sea view room. The room itself is rather basic with a tub with sea views and a nice balcony with excellent beach/sea views by Singapore standards (there are many container ships/oil refineries in the distance). As part of Singapore's rather strict social distancing measures the beach at Sentosa is currently partitioned with part becoming a private beach for the resort. In this private beach section there are water activities and plenty of sun loungers with F&B service from the beach/pool bar. I'm not entirely sure what the current beach situation is for other resorts but most if not all beach clubs are currently fenced off from the beach. The pool is a decent resort pool and has a dedicated adults only section which is appreciated as there are a lot of kids at the resort.
F&B at the resort is much more family friendly than luxury with prices fairly typical for Singapore. During our stay we had cocktails and coconut juices by the beach, cocktails and dessert via room service as well as dinner and breakfast at the Silver Shell restaurant. I thought most things were fine although not great with efficient but not luxury service. Service was generally friendly although not at all personalized. There are some queues at check-in due to a rather lengthly check-in process because of the covid protocols which require health/travel declarations and booking of facilities which is currently the norm in Singapore.
Overall, few tourists will want to visit a Singapore beach resort especially with the current restrictions but for Singapore based residents this is a decent option given that current travel restrictions eliminate all nearby beach destinations.