I'm hooked on the Conrad Bangkok. (Caveat, I'm a Hilton Diamond member, so I get upgraded and I get Executive Lounge privileges).
They have a free shuttle to the BTS..or you can walk it...5-7 minutes. However, ever since April 2023 I've had nothing but problems with my right foot. Short walks around the mall, walking from the lobby to the elevator to my room, walking from the elevator to the pool are no issues. But I used to love walking up and down Sukhumvit and unfortunately, won't be able to for at least the next year.
Anyway, the Conrad Bangkok ticks all the boxes I need for a hotel...affordable, big rooms, powerful shower, guest friendly, free breakfast and outstanding/friendly/helpful staff.