Looking for advice in teaching in thailand ,

So I’m looking to pivot into teaching and I thought teaching english in thailand might be the easiest way to start considering my background isn’t in teaching or childcare- manufacturing/food/skincare, marketing/writing/startups mostly.

I also have an undergraduate degree in business and canadian citizenship so my first question is whether i’d need TEFL certification or even just a free course to understand the style of teaching.

Secondly which areas would be best to earn over 1000USD, and still be able to save a few hundred USD a month ? Also, as a first timer would it be better to go through a hiring agency or platform? (Or chain of known international schools)

Lastly is it better to secure the job & visa first, or visit thailand and get the job in person, and then change the visa from tourist to working after?

I know there are a lot of questions i’m probably missing but i’m hoping these will give me a clearer picture to start the process on my end.