Get a sim from true or dtac, head over to the AIS store and ask to transfer your phone number to them. Then ask the store what pre-paid package you can get. You'll get 20GB, 5G for 300 baht a month, as a thank you for changing to AIS.
because it's much easier and almost every place, even little stands in the market, have QR codes for payments. And you don't need to have those coins on you
And I have applied for tourist visas in KL twice. It's quick and easy if you have all the documents you need and they just built an indoor waiting area so no more waiting in the sun or run outside.
Check the website for the latest requirements and make a reservation for your application.