Looks like fungus, brown patch most likely

 

I thought about that, but the wettest part of the lawn that never dry seem to be doing just fine.

realistically, I very well may not be keeping up if my soil is compacted clay.

 

Its fungus. Spray curative rates every 2 weeks of azox and propi or Eagle 20

 

Fargo here. From a distance, looks more like heat stress, but you definitely have rust which is odd in my experience because I thought that's more of a thing in the fall. Definitely go with Azoxy. Propi is like the cheapest, but it slows down the growth of your grass which is not what you want with rust, but it at least covers some Dollar Spot that Propi does not touch. It's better and arguably cheaper to put them preventive rates of fungicide instead of waiting until you need higher rates.

How much Nitrogen do you have down this year? I suspect it's less than ideal.

 

Yea the one photo I agree is rust. I wasn’t sure about others. I did a curative blanket spray of Eagle 20. I’m up to 2-3#N but mainly to make up for leaching after all the crazy rains we had. Planning to start blitzing mid August.

 

Let’s throw another variable in… those spots probe about 1in with screwdriver. Still think it’s all fungus?

 

Some fungus thrives in drought stressed turf at times so sounds like both fungus and drought stress.

From your pH, I'm not sure if you have clay like in Western MN, but what I think helps is "Cycle and Soak" if your irrigation supports it. Basically if I set it to 30 minutes per zone, It will run a Zone for say 10 minutes then move on to cycling through the different zones. This is to prevent runoff and give the clay time to soak it in. I just checked like 10 spots with a screw driver and all, but 2 spots (went in like 2") went all the way in.

 

Right now depending on weather and water it can be tough to tell fungus feom heat stress. Look closely for lesions and Mycelium or greasy brownish wet look to tour grass pythium …..
I use flags to mark potential fungus area and monitor closely for any issues.
Heat stress at least for me just goes green to pale tan with no yellowing or lesions .
Heat stress seems to me anyway cause what I call standing dead grass. It looks “dead” bit its not. Sort of like seed stalk die off

 

Another photo. Trying to understand why this happened. Did I put too much nitrogen? Microgreene? Screw up the biome? There’s a solid line along the neighbors lawn

View attachment 51642

 

Another photo. Trying to understand why this happened. Did I put too much nitrogen? Microgreene? Screw up the biome? There’s a solid line along the neighbors lawn

View attachment 51642

My thinking with a cool season lawn in the summer is less is better I'm just trying to make it survive the summer I just keep it watered and react quickly with any fungal issues. Come early fall it's game on I start pumping nitrogen