What's your question? Ask

I like to power rake the lawn hard so it really digs down well. Rake away all it brings up. Then apply a one step seed such as the one at this link: https://www.homedepot.com/p/Pennington-8-3-lb-One-Step-Complete-for-Dense-Shade-Mulch-Areas-with-Smart-Seed-Mulch-Fertilizer-Mix-100520284/205599918 And then water things well. You could even lightly sprinkle some top soil over the top of the entire lawn after applying the seed. I do mean lightly too so as not to make a nasty muddy mess. Mine came up great and I enjoy my trees too!

I recommend applying dolomitic lime to your yard. This will raise the pH and counteract the large amounts of urea in the soil. This should help significantly.

You can kill weeds with the juice, but there would be no purpose to purposely put one on your lawn. Maybe someone threw one out, and that could be the reason that it is there. Otherwise, there will be no good reason to do this.

There are chemicals made for grubs in lawns. Here are details on what is available and what not to use: http://msue.anr.msu.edu/news/how_to_choose_and_when_to_apply_grub_control_products_for_your_lawn
Timing is crucial for effective control. Contact your state's cooperative extension service for when to apply insecticides in your area.

This can be a process, you will need to first determine where the water is coming from.
You will need to determine if your soil is draining properly.
You can do a test to see how long it takes for water to drain in your soil.

You may need to call in professional help to create drains in your yard to drain excess moisture.
These links have more information.

https://www.treepeople.org/sites/default/files/pdf/resources/How-to%20Test%20Soil%20Drainage.pdf

https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/yard-drainage-problems.htm

https://www.gardeningknowhow.com/ornamental/foliage/moss/killing-moss.htm

It sounds like the ants are destroying roots in the area by building their nest. I recommend getting rid of the ants. You can use boiling water, or an insecticide to do so. Then you will want to repair the soil by using dolomitic lime, and wettable sulfur. After this, and about a week's time, you can reseed the area.