I've just seen that SCB have updated their app... unfortunately my device only has Android 7.1.1, which is no longer supported. And I'm in the UK with my wife at the moment, don't expect to back in Thailand for a few months.
So I tried setting it up on my wife's iPhone (with a version of iOS that meets their requirements)... the app installed, I was able to remotely register it, and can login *sometimes*... when I try to log in, I either get the message in Thai "cannot process" and can't login, or I can log in but clicking on the bit I want to access (e.g. Account Summary, Transfer Money) opens a box telling me what that section does - but it doesn't open that section!
SCB's advice via their customer service email... "your device is not compatible, we recommend getting a new device". And their advice via their LINE support line... "fly back to Thailand".