If you prefer to do everything yourself including going to the immigration office and and making sure you have all the necessary paperwork in order that I would recommend doing it in the US before you fly here. If you want to trust a company to do all of that for you then talk with an agency that specializes in immigration. They will tell you to do it once you get here. I used it agency and they took care of all the hassles for me and I am glad I did. I would rather spend the money and have a professional do it for me.
Best and affordable are two different things. I have found that affordable agents can't get things done as well as other agents that cost more. If your goal is to get things done right the first time and not have to worry about it then that it's going to cost you a little bit more
I use a free VPN (Proton VPN) that is connected to a number in the US, sometimes you have to keep changing servers to get a US server, then I use Google voice and it's free. Both items are free
I stopped using Wise because of the large amount of complaints and their transfer fee went from $6 USD to $22 USD. I use Remitly now. Fee is only $1.99 and the net transfer is only about 50 Baht lower.