Aurora R11, audio lag between input and output

New in September 2020. I am getting a noticeable lag between the input and output jacks on my built-in Realtek ALC3871 sound card.

My signal chain is:  Zoom R16 Mixer > Dell/Alienware Aurora R11, with Windows 10 Home > PC speakers. The Zoom output plugged into rear panel sound card input. Speakers plugged into rear panel sound card output.

When I play back on the Zoom there is a lag between headphones plugged directly into the Zoom (real time) and the PC speakers (delayed).

I have updated all Windows/Dell updates and Realtek drivers - no joy. Disabled Exclusive Control and Exclusive Applications Priority - no change. Installed Windows drivers in place of Realtek drivers = slight improvement.

First call to Dell support changed nothing. They want to blame it on the mixer. Mixer is not the problem - just the source of the input signal.

I understand the Realtek is not a high end card, but is this the best it can do? Not looking for studio quality - just real-time in and out!