I work online also - also require quality network. I use cellular, never rely on hotel internet. I can't really tell you about specific places most places in Bangkok have great cellar. However, sometimes there will be interference from other buildings or what have you.
I work for a company in the US. So speed from TH to US is what is important to me.
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Will give you just that. 250ms latency may sound scary but its never been an issue with zoom or other video conferencing. You may try to ask some of the hotel staff to test on their phones, send you a screen shot.