Great question — if I only had one night in Macau, I'd probably go with 18 Sauna or Golden depending on what vibe you're after. 18 has that classic Macau experience with lots of selection and solid service, while Golden tends to be a bit more upscale.
Also, if you're open to exploring outside the sauna scene, check out
https://diva-escort.com/ — they list some high-end companions in Macau that might be worth considering if you want a more private experience.
Let us know where you end up and how it went — always helpful for the rest of us planning trips!