I do not think you have to reduce the emphasis on the "Resend by email" option.
Consider this: People will only want to receive OTP by email if SMS is not available or reachable. The most primary thing, in this case, will then be to enter OTP. Based on this primary action, we can assume that whatever medium the user prefers to receive the OTP should be made discoverable to them.
I have provided 3 options.
Option 1: layered button on the keyboard, that allows for either option.
Option 2: Both of them in the same layout, but positioning SMS at the top.
Option 3: Just basically send OTP to both phone and email to start with. There could be a debatable security concern here, but users can receive OTP via either anyway, so why not just send to both and save users some cognitive load in those rare occurrences.