Of course : whether Wise or Revolut, there NO hidden cost, the app show you exactly what you will get, same amount credited on your account, nothing more nothing less - which what I did completing the transaction with Revolut. Wise basically has 0.67% transaction fee for THB, Revolut only the interbank rate which is a bit less, except on week-ends.
Wise takes 0.67% - this is a mark up on top of the mid market rate. I made the change for real with Revolut, I got the mid-market rate with NO mark up - that was 3889.44THB on my Revolut when Wise was giving me abt 200THB less.
My guess is that the bank may share any information through CRS as soon as you opened an account with them showing that you are a foreign national - like ID documents, address abroad, etc.... which is likely to be the case for you in Thailand...
I have been using Private Internet Access for years (inexpensive) but both speed and support got worse and I switched to Nord VPN, clean interface and very fast (I have a 500mps connection and close to zero trade off in speed) Pricing is on the moderate side. If you go for free VPN, you won't get the same speeds.