OT Burying a Cultec Access Port

We are finally starting the landscaping work and they will need our decision soon about how to position the Cultec Access port shown in the photo below. One point of view is to cut the 6" pvc about 6" below grade—leave the white cap on—and triangulate the exact location should maintenance ever be required, which some people are assuring us will likely never be required. One reason cited is to not interfere with the grass root system.

I prefer keeping the port only a few inches below for easier access. To me a 6" wide port is not a big impediment to grass root growth. Roots could easily find deeper soil a few inches away. I suggested something like the green lid below but was told it can't attach properly, so maybe the pvc white cap is best. Any ideas?

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