Queries on buying an eSIM at Siem Reap International Airport

I’ll be landing in Siem Reap early in the morning at around 6 AM. Have a few queries on the same.

1. Will the shops / counters selling eSIM be available early in the morning at 6?

2. I’ll be in Cambodia for 3 days. I need around 3 GB of data per day. How much should an eSIM ideally cost?

3. Which network works the best in terms of connectivity and net speed in Siem Reap?

4. Are credit cards accepted as a method of payment to buy the eSIM? Or is cash (USD) the only option?