I recently got to know that enabling adb and USB debugging increases the attack surface of the device very high, but I had it enabled for a short period of time for a app, but then disabled it. Is the attack surface now permanently high or not?
As long as you didn't connect any malicious USB peripherals when it was enabled, you should be fine.
You may want to set
Settings -> Security -> USB Accessories to Allow new USB peripherals when unlocked or Deny new USB peripherals.
Settings -> Security -> USB Accessories
vky17 Ok thanks for your info!