Please stop using Ardour 4.x immediately and get Ardour 5.12
2 Ardour’s own ALSA audio/MIDI backend cannot be used with different input and output devices. This is not a recommended way to work with pro-audio. If you really need to do this on Linux, you will need to use JACK (though it is still not a recommended way to work).
You can do that if you wish, but your fundamental problem remains the same whatever you do. All digital audio work should be done with a single sample clock. If you use multiple digital audio devices (like a USB microphone and some other device for listening) then there are 2 sample clocks.
You may not notice the problems right away. You might not notice them ever. But this is not the correct way to work with audio, and companies like Audiotechnica should be ashamed of themselves for selling this sort of equipment as if it is sort of “pro”.
For the record, if you do this on macOS, it doesn’t get rid of the problems - the OS just hides them and does what the “complicated JACK-based solution” does, but out of sight.