What's your question? Ask

This is a pattern seen in zoysia grass when it is extremely dry and under fertilized. Water and a nitrogen rich fertilizer should help restore the lawn.

https://www.gardeningknowhow.com/lawn-care/specific/zoysia/zoysia-diseases-tips-for-dealing-with-zoysia-grass-problems.htm

It sounds like a fungus, maybe brown patch but there are many others it could be. The toadstools, humidity and frequent watering are all indications of a fungus. First, allow the grass to dry out some as fungal spores thrive in moist conditions. Then treat the area with a fungicide. In choosing fungicides, you may need to select one targeted to the specific problem, as they work differently. That being said, conditions such as brown patch can be treated effectively with Banner, Daconil or Bayleton fungicide. For additional information, these articles may help: https://www.gardeningknowhow.com/lawn-care/specific/zoysia/zoysia-diseases-tips-for-dealing-with-zoysia-grass-problems.htm
https://www.gardeningknowhow.com/lawn-care/lgen/grass-fungus.htm

This article will help with fertilizing zoysia:
https://extension.missouri.edu/publications/DisplayPub.aspx?P=G6706#Maintaining

You should not sow or plant anything in summer. The heat from summer lesses the chances of survival as the roots are unable to establish. You want to resod in cooler temps, preferably early spring or fall.

Here is a great link for you.

http://www.clemson.edu/extension/hgic/pests/weeds/hgic2310.html

Zoysia grass is a very invasive grass. It can be difficult to control. Small areas of Zoysia can be treated with a non-selective type herbicide, such as Round-up. However, this type of herbicide can potentially kill any plant it comes in contact with, so be careful when spraying around plants you want to keep!

For best results, apply the herbicide when the Zoysia grass is still green, actively growing and not dormant or under drought stress. Since Zoysia grass may regrow, more than one application will probably be needed. Since Round-up dissipates rather quickly, it shouldn't pose any problems with future planting.