That's what I thought. I thought my bank Bangkok Bank. required Wise to make a special desgination that the funds come from overseas, otherwise I couldn't use those funds for things like buying property or proof of funds/income.
I don't know it, but I have a friend from the US who tells me it's better to get the retirement visa within the Thailand. This is because of insurance. Just something for you to look out for.
I have used Agents bunches of times and I have no complaints. However, I think it's better to not use an agent if possible. I concern that once you start with the agent you'll be stuck using the agent.
Another problem I have had is where I open my bank account. For many of your interactions with your bank, you will have to go to the branch where you opened the account. If you open an account in Bangkok then move to Samui, you may have to travel to Bangkok to get your banking paperwork... There may be ways around this but do you really want the hassle.
I would recommend coming on an METV or DTV, figure out where you want to live for the next five years and start working on the requirements to moving here (seasoned bank account, purchase/lease condo, etc etc).
For the past 10 years, off and on, I have used METV and done border bounces to get a new stamp. Yesterday I was in Cambodia for about 15 minutes to get a fresh stamp. I am starting to think it's pointless because they stamp you in for 60 days regardless if you have a visa... But I am cheap bastard so I intend to get my money's worth.
In those 10 years I have been pulled aside twice. Once in the airport once at a land crossing. They talk to you, ask you a few questions and send you on your way. This is a great opportunity to be a jerk, say something really stupid then get denied entry... However, if you can manage to be a half-way decent person, complement Thailand, Thai people and Thai food, they will likely stamp you in no problems.