What is the application process and payment timeline for the LTR visa for remote workers in Thailand?

Many people have it. The first thing you do is apply through the BOI. They are the one that makes all the decisions so you should ask them any questions.

Once you're approved they send you notification and then you tell them whether you want to apply for the visa at your Thai embassy outside of Thailand or if you want to pickup the visa in Bangkok at their office.

You pay after you're approved, either as part of your application to the embassy, or you pay directly to the immigration office next to the BOI when you go to pickup your visa.

I recommend getting it in Thailand because then you'll pay exactly 50,000 baht. If you apply at the embassy you'll pay more because they all use a fake exchange rate that will cost you hundreds of dollars more.

There's no reason not to apply if you think you qualify. It's free to apply and you'll find out if you're approved before you have to pay anything.