I agree with the reply above: Thong Lor/Phrom Phong is probably what you'd want. Near Thong Lor is a pretty decent looking Marriott and just next door is a new Intercontinental. You're too early for what I believe will eventually be a Conrad? next to EmSphere, but in the soi behind the park is the Marriott Marquis. For Hiltons, there's a Hilton in Sukhumvit 24 and a DoubleTree in Sukhumvit 26. Practically every chain is represented from Asok to Thong Lor.

The stretch from Asok to Ploenchit is a hellscape. Between Ploenchit and Siam is the busiest commercial district. Upscale choices would be Park Hyatt at Central Embassy and Grand Hyatt Erawan. Towards Ratchadamri station are Anantara and St. Regis. A slightly more budget choice in a soi off Ratchadamri is the Courtyard by Marriott, which I have a soft spot for since it was where I (twice!) served my covid-era quarantine.

All of those hotels have extensive threads in the hotel forums on this website.