Was passiert mit meiner Eiche, Austin TX?

If this were my tree, say I moved in and found this tree, I would assume it is dying a slow death. There is a healthy roll of tissue trying to cover the massive wound on the lower part of the trunk, but I don’t know if the tree can outgrow any rot developing inside the wound. The bark peeling off makes me think my best option is unfortunately cut it all down before it falls down. Things I may do are remove ALL the plastic mulch and leave only stone mulch under the canopy all the way to the drip line. I would leave the plastic border in a circle outside the drip line so string trimmer can keep the lawn out of the tree root area. In other words, no grass under the oak tree. Reduce watering the lawn that borders the drip line to slow down rot.

Disclaimer: I am not an arborist but I did complete my county’s Master Gardener program in California.

Edited for clarity.

I lost the post from someone that gave me a lengthy explanation on what was happening to my oak tree, very much appreciated. You said I should take out the black plastic cover under river rocks? You also mentioned if there were acorns I should plant some so more trees would grow. In this small area I have 9 trees. I did have a large plastic dish that I would put water for squirrels and birds and every 3 days I would dump the water next to the sick tree!!! I moved the dish and put it where there are no trees.

https://preview.redd.it/lj4pcmuzxayf1.jpeg?width=3024&format=pjpg&auto=webp&s=916825bd500bab3ff18fecf8298cb659421df0cd

the sick tree is closest to the pool deck.