Sending money to your Balance is totally free as long as you do manual transfers from your bank account back home to Wise's local bank account. The fee is a bit cheaper when sending money from the Balance to your Thai bank account. The idea is that you can keep money in the Balance and use it like a common bank account. For some currencies you can even earn some interest.
Where are you staying? The procedure isn't exactly the same when it comes to documents needed. It differs a bit between immigration offices. Do you have a TM30 receipt in your passport. It's crucial at most offices and non-negotiable.
Do you really think that every person trying to open a bank account is staying in Bangkok? I'm staying in Jomtien and when on a long term stay,like a non-immigrant O, there's no problem to open an account at Bangkok Bank as long as you meet the requirements.