You have certainly invested a lot of heart into your tree. Giant Sequoia have limited success in WV as they do not tolerate clay soil well. They prefer cool conditions (max summer temps of 75-84), require well drained, sandy soils, and do not tolerate drought.  

1. After being grown in a pot for 5 years I worry that the roots may have grown in a circular pattern. Additionally, when there is a lot of clay in the soil, a planting hole can act like a pot leading to more encircling/girdling roots which reduce available nutrients and water and can eventually kill the tree. I am going to assume that you followed proper planting techniques by keeping the root collar at or above the soil line, cutting any encircling roots, and roughing up the edges of a wide shallow hole.  

2. Our weather in 2019 was extremely wet. Soil saturation in much of the state made many of our conifers more susceptible to root diseases. This was followed by an extremely dry summer in 2020 which further compounded the stress factors on our conifers. Your Sequoia would be especially susceptible to problems associated with poorly drained soil and drought.

3. While we have the preferred acidic soils in a lawn environment the clay in our soils may lead to compaction further reducing drainage.

Steps to take to reduce tree stress:

1.    Do NOT fertilize. This will cause your tree to put effort into building new growth instead of fighting whatever is impacting it. 

2.    Get a moisture meter (about $35) monitor once a week until the soil freezes. When moisture levels drop, slow water your tree (use a bucket with small holes drilled in the bottom set outside the leafy area).  Your tree will need about one gallon per inch of diameter (4.5 feet above the soil level on the uphill side). However, if the soil shows it is moist at any time stop watering.  If you notice that your soil is often moist due to a drain or seep, moving the tree to a drier area may be needed.

3.    Add mulch, and a lot of it. This will most importantly help improve drainage and balance moisture, but it will also protect it from mower damage, add nutrients, and keep the pH where it needs to be. Gathered oak leaves and pine needles would be perfect but anything that can decompose will work. Give the tree as wide of a mulch ring as you can tolerate.  Grass is very greedy and steals nutrients and water (putting a layer of newspaper, woven ground cover, or landscape fabric under the mulch will keep the weeds down but do NOT use solid plastic.  Keep the mulch at least 6” away from the bark to avoid rodent damage and rot.  

4.    Keep an eye on the tree.  Use a magnifying lens to examine the needles for black dots and check the base of the tree regularly for damage.

5.    Aerate your lawn using a plug aerator every fall.  This will reduce the general compaction caused by your lawn mower.  Reducing how hard the roots have to fight to get access to nutrients and moisture.  This will improve drainage for your tree and the health of your lawn. 

Best of luck in nursing your tree back to health!