Hi..
I'm currently in Singapore, and I'd suggest you follow up with with your plan.
A quick self-swab ART will be done in minutes. and you can book a much cheaper city hotel.
You can book Gojek with 10$ discount to the city using code "Goairport" (you can't use the MRT unless you're recovered from Covid) making a trip to the city centre below 10$.
Hotels are about 100$ for a decent 4*, so definitely go for that. Bars still mostly close quite early (10pm), but it's enjoyable for sure. Beer prices are quite low at the moment with many places running heavy discounts. 6-7$ for a pint of decent beers is quite normal, or 1-for-1 even at Clarke.
When will you be here? Happy to meet up for drinks and food (Hot Pot?)